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Car Forum / Ford / Ford Trucks / October 2007Ford Auto Hubs can cause spectacular failure
I had quite an experience coming home from vacation this year, and I'd like as many people as possible to be aware of the problem, and how to avoid it. Briefly, the automatic front hubs on my 2000 F-250 failed, and were stuck in locked position. This happened once before, and the hubs were replaced (10k miles and well over the 12-month warranty period). This places a lot of stress on the drive train, and in my case the CV joint (on the front axle) failed. This caused the crank-case and transmission to literally explode, sending chunks of metal flying all over I-80 in Wyoming. One chunk, in fact, struck the under-side of the pontoon boat I was towing; had the boat not been there, it might have been somebody's windshield. This pickup has almost always seemed to bind in turns. I was aware that this happens in 4wd (no positraction up front, which is normal). I was not aware that the hubs might be stuck, nor was I aware of the potential consequences. Since the dealer had told me everything was OK a couple of times I complained, I just assumed that was the way the pickup drove. Wrong! From the Internet searches I have done, as well as talking to some repair shops, it appears to me that Ford's are especially bad for this. Apparently the hubs use some type of vacuum to disengage, and that's what people seems to fail. What I would REALLY like to have happen is everyone with a 4wd pickup, with auto hubs, go out and make a couple of hard turns (cranked all the way). If there's any binding, and it kind of jumps through the turn, you should have the hubs checked immediately. If you want to know what the "feel" is I'm trying to describe, just put it in 4wd and try a hard turn or two. Note that if your hubs ARE defective, a REALLY good thing to do would be to log it on the NHTSA's web site. You can file a complaint here: http://www-odi.nhtsa.dot.gov/ivoq/ If enough people do that they will investigate, and potentially issue a recall. What I did (besides "invest" $5,500 in a new crank-case an tranny) was to replace the Ford hubs with Warn manual hubs. I will never have the same issue again -- besides, the Warn hubs are a lot cheaper. For Ford's part, they have taken the stance that all parts are out of warranty (which is true), so they have no financial responsibility. I feel that NO vehicle should EVER scatter metal on a highway (an opinion also expressed by the NHTSA investigator I talked to), and that Ford should acknowledge that and at least help me out. I'm probably going to see how hard they decide to fight me in court. I would be VERY interested in hearing from anyone else that's had their hubs fail to unlock (or lock, for that matter), especially if it caused additional problems. I created a yahoo account just to keep replies separate, and would greatly appreciate any feedback or ideas. Rob (robs-f250@yahoo.com) > I had quite an experience coming home from vacation this year, and I'd like as > many people as possible to be aware of the problem, and how to avoid it. [quoted text clipped - 47 lines] > > Rob (robs-f...@yahoo.com) Hmmm. 2004 Explorer automiatic with 4WD, 97 Mazda B4000 5-speed 4WD. Don't use the 4WD on the Explorer very often but the B4000 4WD gets a lot of work. Never had a problem with hubs except that now and then the Mazda goes "zzzzzzz" when the front hubs don't release -- drive about 10 feet in reverse and they release. Still, I'll go out and do a few hard turns in both 4WD and 2WD at slow speed and at as high speed as I dare to see what happens. Explorer does not use the autolock hubs on the Super Duty. >> I had quite an experience coming home from vacation this year, and I'd >> like as [quoted text clipped - 88 lines] > Still, I'll go out and do a few hard turns in both 4WD and 2WD at slow > speed and at as high speed as I dare to see what happens. > Explorer does not use the autolock hubs on the Super Duty. Hmmmm. Okay. I'm not sure what that means or doesn't mean. I'm NOT an expert on 4WD. This is what I have always done: -- Don't use 4WD on hard-surface roads, or on dirt or gravel roads where the vehicle is humming right along in 2WD. -- Use 4WD ONLY when the vehicle is spinning the wheels or not pulling in 2WD. As long as 2WD is moving me along, I stick with it. -- Every so often -- about every six weeks or so -- I get onto a rough, uneven surface -- I use a nearby road with loose gravel and a steep uphill grade -- and go into 4WD for a short distance to keep the hubs, etc., lubricated. My Explorer has three buttons on the dash -- 4AUTO (normal), 4WD LO, 4WD HI. My understanding is that in 4WD AUTO it will drop into 4WD or AWD automatically when the rear tire(s) lose traction then shift out when it's not needed. With the Explorer in 4WD HI or LO (which I did a good bit getting around after Hurricane Katrina) the steering was "different" -- not difficult or anything but steering took a bit more effort that usual. In my Mazda B4000, when it's in 4WD LO or HI, the steering is MUCH different, especially in a somewhat sharp turn. Is this normal? Thanks. Super Dutys with electronic shift on the fly 4wd have autolocking hub locks which are supposed to spin free when the vehicle is in 2wd, but have a provision for manually locking in case of hub lock malfunction. Dial on the dash says "2Hi, 4Hi, 4Lo. Standard shift 4wd have manual locking hublocks that have selectable dials. Transfer case lever positions are 2Hi, 4Hi, N, 4Lo. Explorers don't have any kind of hublocks, the front drivetrain is engaged but freewheeling when in 2Hi. >> Explorer does not use the autolock hubs on the Super Duty. > [quoted text clipped - 24 lines] > > Thanks. >> I had quite an experience coming home from vacation this year, and I'd >> like as [quoted text clipped - 88 lines] > Still, I'll go out and do a few hard turns in both 4WD and 2WD at slow > speed and at as high speed as I dare to see what happens. IKf you perform this test in 4WD on dry pavement, you should expect to feel binding and a wobble in the steering wheel. This is perfectly normal, and it is your sign that the 4WD system is not happy with the crap that you are making it do. > >> I had quite an experience coming home from vacation this year, and I'd > >> like as [quoted text clipped - 95 lines] > > - Show quoted text - I put the Mazda into 4WD HI on dry pavement, drove slowly about 20 feet straight ahead, tried to make a right-turn and the truck told me that was not the right thing to do -- end of experiment. > I would be VERY interested in hearing from anyone else that's had their hubs > fail to unlock (or lock, for that matter), especially if it caused additional > problems. I created a yahoo account just to keep replies separate, and would > greatly appreciate any feedback or ideas. > > Rob (robs-f...@yahoo.com) As amazing as this might seem in 2008, somethings do still require you to have a clue. You can't run a truck with the old part-time 4x4 system on drive pavement or the drive-line grenades. Just pushing the button on the dash doesn't necessarily drop you out of 4x4 as you found out. Calvin Actually, if the automatic hubs are working properly they are supposed to unlock as soon as you take it out of 4wd. That's the whole point of auto hubs. The problem is (as I found out) they don't always work right. That's why I now have manual hubs -- cheaper, and won't have the same problem again. Rob >> I would be VERY interested in hearing from anyone else that's had their hubs >> fail to unlock (or lock, for that matter), especially if it caused additional [quoted text clipped - 11 lines] > >Calvin Yes, but the transfer case disengages as well, so even if the hublocks are engaged, you still won't be in 4wd if the T case is in 2wd. > Actually, if the automatic hubs are working properly they are supposed to > unlock [quoted text clipped - 24 lines] >> >>Calvin The trouble that auto hubs have is that they do not LOCK properly. The vacuum system that engages the hubs will fail, and the hubs will consequently refuse to engage. If the vacuum is lost, the hubs unlock and 4WD is disabled. When the 4WD system fails to unlock, it is physically bound up and can not unlock. If this is the case, you must stop and go in Reverse a few feet to allow the stress of the previous 4WD operation to be released. If you were engaged in 4WD operation, then pressed the button ot return to 2WD, but did not provide the environment for the system to release, then you could easily get on the highway and drive for hours in 4WD, thinking all the while that you are in 2WD. You will like the manual hubs. Set them at the trail head, then shift into and out of 4WD as you need. If the weather sucks, then you can leave them locked, and avoid getting out in the snow or rain to unlock the front end. My front hubs have been locked for going on 10 years ... > Actually, if the automatic hubs are working properly they are supposed to > unlock [quoted text clipped - 24 lines] >> >>Calvin > You will like the manual hubs. Set them at the trail head, then shift into > and out of 4WD as you need. If the weather sucks, then you can leave them > locked, and avoid getting out in the snow or rain to unlock the front end. > My front hubs have been locked for going on 10 years ... And be sure the transfer case shifts out of 4wd. Even sometimes the indicator will show it but tension on the drivetrain will keep it in 4wd. You can back up to be sure, but usually shifting the transmission into neutral will relieve the bind and allow the T case to disengage. >> Actually, if the automatic hubs are working properly they are supposed to >> unlock [quoted text clipped - 28 lines] >>> >>>Calvin > I would be VERY interested in hearing from anyone else that's had their > hubs [quoted text clipped - 5 lines] > > Rob (robs-f250@yahoo.com) OK, here's my feedback. You obviously don't understand how four-wheel-drive works. Your transfer case (NOT crank-case) was in 4wheel drive on the interstate. That's what destroyed it. Just locking the hubs does not mean you are in four wheel drive, the hubs engaged and the T case in 2wheel drive means the front driveshaft is spinning, but just freewheeling. This is what happens to other makes (Jeep, GM, Dodge) which don't have front hublocks in their four wheel drive vehicles. If the hubs fail to unlock, it doesn't really cause all that much stress on the drivetrain. I have had an F250 with the problems you described, but never had any catastophic failures. Granted, the vacuum operated autolock hubs are bad design, but the hubs alone wouldn't have cause your transfer case to explode. You must have been in four wheel drive on a high traction surface on a regular basis, which you should NEVER do. >> I would be VERY interested in hearing from anyone else that's had their >> hubs [quoted text clipped - 22 lines] > explode. You must have been in four wheel drive on a high traction surface > on a regular basis, which you should NEVER do. Yes those auto hubs were pretty unreliable on my 95 f150 4x4. i replaced with warn manuals F150's didn't have the same hubs as Superduty, but I would agree with you in general, autolock hubs are pretty unreliable. >>> I would be VERY interested in hearing from anyone else that's had their >>> hubs [quoted text clipped - 25 lines] > Yes those auto hubs were pretty unreliable on my 95 f150 4x4. i replaced > with warn manuals >>> I would be VERY interested in hearing from anyone else that's had their >>> hubs [quoted text clipped - 12 lines] >> interstate. That's what destroyed it. Just locking the hubs does not mean >> you are in I would agree with this. This is a very simple explanation, where the OP's explanation required a long sequence of events (made up, obviously) that don't seem to be plausible. >OK, here's my feedback. You obviously don't understand how four-wheel-drive >works. [quoted text clipped - 12 lines] >explode. You must have been in four wheel drive on a high traction surface >on a regular basis, which you should NEVER do. Everything falling to pieces appears to be rare. I definitely did not have the pickup in 4wd, and the only time I ever have driven it in 4wd on dry pavement is when pulling boat from the water, and I'm good enough backing I don't make any hard turns. According to the guy that repaired my vehicle, as well as a Ford mechanic I talked to, driving that pickup over 45mph with hubs locked is a big no-no, and does cause a lot of stress. The owners manual stresses no 4wd over 45mph, but didn't say anything about hubs locked. Rob Let me repeat: LOCKED HUBS DO NOT EQUAL 4WD. Unless your transfer case was in 4wd as well, there is NO WAY locked hubs could have destroyed your transfer case. Your transfer case was either in 4wd, or malfunctioning, or it disintegrated for another reason, but I can guarantee you it had NOTHING to do with locked hubs. Driving with locked hubs with the transfer case in 2wd is PERFECTLY ACCEPTABLE at any speed. The 4wd systems made by Jeep, Chevrolet, & Dodge work this way because they are not equipped with selectable hubs. The front drivetrain spins all the time, freewheeling in 2wd, engaged in 4wd. I drove around with my F250's auto hubs engaged for a week before I was able to take it in to be fixed. No problems. As long as the transfer case was not in 4wd, I was OK. You seem to be under the impression that having hubs locked means you are in four wheel drive. This is not the case. Either you misunderstood what your mechanics told you, or they don't know what they are talking about. When I brought my truck in the first time, even the service guy was clueless...he thought I was in 4wd simply because my hubs were locked. Driving with one hub locked and one unlocked isn't a good idea, but that wouldn't hurt your T-case either. > In article <9rKdnbIMcbB29mDbnZ2dnUVZ_oSnnZ2d@comcast.com>, Matt > Macchiarolo [quoted text clipped - 8 lines] > > Rob > Let me repeat: LOCKED HUBS DO NOT EQUAL 4WD. Unless your transfer case was > in 4wd as well, there is NO WAY locked hubs could have destroyed your [quoted text clipped - 6 lines] > work this way because they are not equipped with selectable hubs. The front > drivetrain spins all the time, freewheeling in 2wd, engaged in 4wd. ... As the CIA guy said to the President in the 4th of July movie.. Um, that's not entirely accurate. If one hub were to lock in, and the other hub were to freewheel, you could blow up the center section. Not as easy certainly, but it will eventually fail. The differential will over-speed, a bearing will seize, and if you keep going with that noise, it'll likely have a gear fracture and send stuff out the side of the housing. 4wd systems are complex and I'm shocked at the number of 4wd systems on the road where people don't have a clue. the AWD systems are really what people that don't have a clue should be using. They are more expensive, but they require less thought. >> Let me repeat: LOCKED HUBS DO NOT EQUAL 4WD. Unless your transfer case >> was [quoted text clipped - 21 lines] > seize, and if you keep going with that noise, it'll likely have a gear > fracture and send stuff out the side of the housing. That's not what happened to the OP. Also, I mentioned this scenario in a previous post as "not a good idea." And that's why when the left hublock on my own F250 failed to disengage, I manually locked BOTH of them so as to keep the center diff spider gears from overspeeding, until I brought it in to be fixed, which was PERFECTLY ACCEPTABLE at any legal speed. > 4wd systems are complex and I'm shocked at the number of 4wd systems > on the road where people don't have a clue. the AWD systems are > really what people that don't have a clue should be using. They are > more expensive, but they require less thought. Can't argue there. >Let me repeat: LOCKED HUBS DO NOT EQUAL 4WD. Have been aware of that from day 1. >Unless your transfer case was >in 4wd as well, there is NO WAY locked hubs could have destroyed your >transfer case. Your transfer case was either in 4wd, or malfunctioning, or >it disintegrated for another reason, but I can guarantee you it had NOTHING >to do with locked hubs. Transfer case wasn't destroyed ... same transfer case is still on the pickup, without any repairs. The crank-case (bolted to the front of the transmission) is what went. The constant-velocity joint on the front axle (between transfer case and crank case) gave out. Mechanic *said* that causes a lot of vibration in both the crank-case and transmission, and is what caused it to fall apart. BTW, Ford accepted the partial transmission as a core (crank-case doesn't have a core charge). >Driving with locked hubs with the transfer case in 2wd is PERFECTLY >ACCEPTABLE at any speed. The 4wd systems made by Jeep, Chevrolet, & Dodge >work this way because they are not equipped with selectable hubs. The front >drivetrain spins all the time, freewheeling in 2wd, engaged in 4wd. Could be ... Ford service manager told me not too, though. >You seem to be under the impression that having hubs locked means you are in >four wheel drive. Nope. Have had 4 4WD vehicles, two with manual hubs, one with semi-auto (explorer, had to back up to disengage hubs) and this F-250, which *claims* to not need backing up. Since taking it out of 4WD the day before, the pickup was in reverse, park, running and off. The old auto-hubs, when taken off the vehicle, were set in "auto", yet were obviously locked (did not turn freely). After playing with one of them awhile (turning to "locked", then back to "automatic") it's loosened up to where it's hard to get them to stay locked. The other one is still rigidly stuck in locked, and I don't intend to touch it. I appreciate all of the answers and discussion. I'm not a mechanic, but I am familiar with 4WD and the basics of how a vehicle works. From the responses I've seen this is obviously NOT a normal thing to have happen. Maybe the hubs weren't the cause of the failure, even though they were stuck in locked. I just don't know. Rob > Transfer case wasn't destroyed ... same transfer case is still on the > pickup, > without any repairs. The crank-case (bolted to the front of the > transmission) > is what went. The engine is bolted to the front of the transmission. The crankcase is part of the engine. It's where the engine's crank is. The top part of the crankcase is the engine block. The bottom part of the crankcase is the oil pan. What was replaced? The constant-velocity joint on the front axle (between transfer > case and crank case) gave out. Mechanic *said* that causes a lot of > vibration [quoted text clipped - 3 lines] > have a > core charge). You really need to be more careful with your terminology, it's too confusing to try to interpret what you mean. The CV (double-U-joint) joint is not on the front axle, it is on the front driveshaft, on the transfer case end, not the end connected to the axle. The centering ball is in the joint on the transfer case end of the driveshaft. Did the joint completely let go and detach from the transfer case as you were driving, or was it still attached when the damage happened? If the drivshaft joint was still together when the ball failed, any vibration severe enough to destroy the transmission would have been felt for a reasonable time before serious damage was done. If it came apart, there normally would have been some vibration & noise for a while as it was failing but before it came apart. It's hard to really pinpoint what happened, the way you tell your story makes it look like the story changes with every retelling. >>Driving with locked hubs with the transfer case in 2wd is PERFECTLY >>ACCEPTABLE at any speed. The 4wd systems made by Jeep, Chevrolet, & Dodge [quoted text clipped - 3 lines] > > Could be ... Ford service manager told me not too, though. He's a moron. > In article <eeudnVU1G7t-AmPbnZ2dnUVZ_hynnZ2d@comcast.com>, Matt > Macchiarolo [quoted text clipped - 62 lines] > I just > don't know. The HUBS did not cause the failure. Clearly you had a failure that was catastrophic, but the hubs did not cause it. Something else caused it. Were it not for whatever that failure was, the front hubs can be locked 100% of the time and nothing bad will result. Having the hubs locked, AND having something actually be wrong somewhere else can set up a problem that quicly becomes a catastrophy, but the hubs are not the cause. The cause is the other stuff that gave up. CRANK CASE The crank case is the bottom of the engine. It is where the crank shaft lives, and all of the motor oil. The crank shaft is connected to the pistons. The crank case is forward of the transmission, that is true. But the hubs would not destroy the crank case. The front drive shaft could (in theory) whip around violently and destroy the crank case, but that would be very noisey for a long time before the catastrophy happened. If the front hubs were locked AND the front drive shaft were compromised then the compromised part could fail in such a manner that the crank case (oil pan) would get beaten to crap. In this instance, you have TWO problems, the hubs not unlocking and a compromised drive shaft. If the hubs were failing to unlock BUT the driveshaft was _not_ compromised, the hubs would not pose a problem at all -- the driveshaft woujld simply whirl around as you drive down the highway. So, bottom line is, you had two problems. The driveshaft was apparently on the fritz and the front hubs failed to unlock. The driveshaft being on the fritz caused the shaft to break and whip all around and take out the oil pan. If that is true, the driveshaft had to wobble and vibrate for a very long time -- I'd suggest weeks, but perhaps only days, at the very least for several hours -- before the catastrophy on the highway occurred. You had problems with this truck that you ignored, the front hubs remaining locked are the least of those problems. How would he have known it was locked i 4WD: If he's just an end user? RK >> I would be VERY interested in hearing from anyone else that's had their >> hubs [quoted text clipped - 22 lines] > explode. You must have been in four wheel drive on a high traction surface > on a regular basis, which you should NEVER do. The way he described the damage, it sounded like he was in 4wd. But his story changes w/ every post, first his transfer case grenaded, then it was his driveshaft that let go and beat up his transmission. Finally he tells us the CV joint on the driveshaft was actually what failed, so his damage was not due to the locked hubs, but to a bad driveshaft joint. And he tell us 2 mechanics told him you should not drive with the hubs locked over 45mph, which is a crock...the hubs can be locked as long as you are in 2wd. If you need 4wd, road conditions are too bad for you to go over 45mph anyway. Granted, if the hubs were unlocked it wouldn't have mattered, but he had a bad driveshaft joint as well, and the hublocks didn't cause the problem with the driveshaft joint. > How would he have known it was locked i 4WD: > [quoted text clipped - 28 lines] >> explode. You must have been in four wheel drive on a high traction >> surface on a regular basis, which you should NEVER do. >I had quite an experience coming home from vacation this year, and I'd like >as [quoted text clipped - 24 lines] > complained, I > just assumed that was the way the pickup drove. Wrong! What you are describing can only happen if you have the truck in 4WD High. 2003 and beyond 4WD Expeditions with those types of hubs leave the front hubs engaged when you are in A4WD (automatic 4WD). Either you stupidly left your truck in 4WD while driving on the highway, or something else is broken. Just locking in the front hubs alone will not cause the sort of problem you are describing. You still have a front differential, and if the drive shaft from the transfer case is free-wheeling, there will be no binding - just slightly reduced gas mileage and extra wear on the front axles. 1999 to 2002 4WD Expeditions didn't even have disconnects on the front driveshafts. The front axles were always engaged. You need to either realize you left the truck in 4WD on the highway, or have the real problem diagnosed. Ed I thought this story sounded odd, and what you and Matt said makes perfect sense, and also explains why Ford wouldn't cover it! Jeff DeWitt >> I had quite an experience coming home from vacation this year, and I'd like >> as [quoted text clipped - 40 lines] > > Ed >> I had quite an experience coming home from vacation this year, and I'd like >> as [quoted text clipped - 40 lines] > > Ed Why is a truck in 4x4 on the highway? > Why is a truck in 4x4 on the highway? Because the operator is a maroon (sic), or the 4WD system is broken. My vote is the former ... I see a lot of replies that are dropping the ball on this one.... SuperDuty ESOF is a lot different from anything I have seen discussed.... What is needed.... mileage on the truck when the failure occurred... and miles on the truck when the last spindle service was performed.... Many owners discount the importance of the large (and spendy) steering knuckle seals regarding proper 4WD operation.... The operation of the auto hubs is vastly misunderstood and, IIRC, I have posted on the subject before.... Having said that.... the failure you describe should have been accompanied by sufficient warning that something was amiss.... at the very least, there would have been a transient vibration.... Not necessarily a "distressing" vibration but it would have been something out of the "normal".... Now...... if the truck will still move, modern logic tells us we can still drive it.... no matter how bad the concern - I'm not picking on you.... I'm talking about too large a percent of my customer base.... By your own admission, "This pickup has almost always seemed to bind in turns.". This is a sure sign that something is wrong. If, after your dealer said "nothing is wrong" and you felt that something WAS wrong... it is time for a second opinion.... Getting back to the hubs.... the hubs are not the weak point.... lack of proper service IS!!! Our shop is almost exclusively centered around SuperDuty 4X4s.... This system is virtually trouble free...... as long as proper maintenance is performed.... Your warning should be "perfgorm proper maintenacne"... not "this system sucks"..... After all... it worked great up until it didn't work any more , right? >I had quite an experience coming home from vacation this year, and I'd like >as [quoted text clipped - 74 lines] > > Rob (robs-f250@yahoo.com) The vacuum operated hublocks on Super Dutys are prone to early failure, I would submit that most owners don't ever touch them so they wouldn't know if they work or not. On my '02 F250, I had two hubs locks (both from driver's side) replaced under warranty due to failure to properly engage/disengage. The first one happened at under 20,000 miles, the second under 30,000. After warranty expired, they failed again at 45,000 miles and I had them replaced with Warn manuals. My current Excursion has had no problems yet, however. >I see a lot of replies that are dropping the ball on this one.... SuperDuty >ESOF is a lot different from anything I have seen discussed.... [quoted text clipped - 109 lines] >> >> Rob (robs-f250@yahoo.com) >I see a lot of replies that are dropping the ball on this one.... SuperDuty >ESOF is a lot different from anything I have seen discussed.... I know the system is not the same as an F150, - however, I can't see where having the hubs engaged should cause binding if the transfer case is in the 2WD position. Here is what I think I understand - A 2000 SuperDuty offered two 4WD systems - a manual system and an electric shift system. The manual systme has manual locking hubs and requires the transfer case to be manually shifted to 4WD. As long as the transfer case is not in 4WD, there should be no binding even if the hubs are locked. The electric shift system electricaly engages the transfer case. The hubs can either be in an automatic mode or a manual mode. If you leave the hubs in the automatic mode, then they are controlled automatically (using vaccum). When you shift the switch on the dash to 4WD the hubs and transfer case are engaged. You can also manually lock the hubs. Either way, unless the transfer case is also shifted to 4WD, there should be no binding. Do you agree? Ed All true, Ed. The OP had his T case in 4wd, whether by ignorance or by truck malfunction. He may have thought it would be safer in the rain. I knew a woman who put her Jeep Cherokee in part time 4wd whenever it rained, she wondered why her front U joints broke...I told her she was lucky it was only that... >>I see a lot of replies that are dropping the ball on this one.... >>SuperDuty ESOF is a lot different from anything I have seen discussed.... [quoted text clipped - 20 lines] > > Ed The act of shifting in and out of 4wd definitely was engaging/disengaging the front transfer case. Every time I've spun back wheels on a slick boat ramp, shifting to 4wd pulls it right out. There's also 4wd roads I would have been able to drive in 2wd. Yet with the hubs set to "automatic", they still were binding in turns (although not as much as the few times I made turns in 4wd). This is kind of what led me to believe a little binding in hard turns was normal. I could definitely see the difference between dialing 4wd and 2wd, and not really understanding at the time the way the hubs worked ... Rob >>I see a lot of replies that are dropping the ball on this one.... SuperDuty >>ESOF is a lot different from anything I have seen discussed.... [quoted text clipped - 19 lines] > >Ed > The act of shifting in and out of 4wd definitely was engaging/disengaging > the > front transfer case. "Front transfer case?" How many transfer cases does your truck have? I think you mean "front axle." The transfer case is what engages the front axle. > not really understanding at the time the way the hubs worked ... I think I found the problem. If, for some reason, the front hubs are locked in, sharp turns will cause the U-joints to bind as the axles rotate.... The single cardan U-joint has a very small range of "stable" motion (about 3 degrees deflection). If the joint is positioned so that it has a large deflection, a whipping motion can set in - the physics of this whipping motion are easy to understand... describing it, not so easy. Simply stated - the cup on the inside of the deflection travels less distance than the cup on the outside of the deflection.... the bug-a-boo being that they are both travelling at the same rpm... Our shop deals almost exclusively with SuperDuty 4WDs... our area is the Great Arboreal Forest that spans much of the mid-north in Canada... Oilfield and logging are our prime industries and a properly maintained front driving axle on one of these trucks is dependable... ("maintain" and "repair" are NOT interchangeable terms). Lets take a look at how this system operates.... When we set the switch on the dash from 2HI to 4HI.... a series of events occurs.... The module that controls the 4WD system (since 99, this task has been assigned to various modules including the GEM, later a stans alone module and currently, that function *may* be in the SJB (smart junction box) though I would have to check to be sure) would command the appropriate transfer case relay to turn the shift motor. When the shift motor indicates proper positioning for the switch position selection, the module assumes that the transfer case is working properly and that the front driveline has been brought to speed... The appropriate 4WD indicator(s) on the dash will illuminate.... After this happens (and only after this), the module will command the PVH solenoid (pulsed vacuum hub).... to lock the hubs, this will be about a 12 inch vacuum signal that lasts for about 30 seconds (memory thing as far as time allotment). Once the time is up, this vacuum signal is vented to atmosphere... it is NOT a continuous application of vacuum.... These hubs operate something like a click type ballpoint pen. Click it once, the point is out... click it again, the point retracts.... To UNLOCK the hubs, the module will command about 6 inches of vacuum to the hubs... again, after about 30 seconds, this vacuum signal is vented to atmosphere. The hubs will not unlock until the vacuum is vented. While the owners manual no longer states it, it is still a very good plan to wait a bit after disengaging 4WD and back up a few feet to remove any driveline bind that may "trap" a hub in the engaged position. Now... 6 inches of vacuum is NOT a very strong signal in anyones book.... If there is a leak in any portion of this vacuum system, the hubs will not have enough vacuum applied for them to operate properly. A trip to motorcraft.com and a looking up the recommended service interval for these trucks indicates that the spindle bearings should be service regularly.... at the same time as this service the large steering knuckle should be replaced, the O-ring around the wheel bearing should be replaced and it's a good idea to replace the axle tube dust seal at the same time. conscientious tech will ensure that the bore in the steering knuckle is clean and free of rust at this time.... So - what else can go wrong if the hubs don't work properly.... Too many owners don't pay enough attention to some of the little clues their autos are trying to give them (the guy that's been driving with the CEL on for two years might be one - the guy that's had an odd vibration for a long time but it hasn't really "bothered" him yet might be another)... until the concern decides that it is time for someone to sit up and take notice.... At the transfer case end of the driveshaft to the front axle, there is a double cardan U-joint. This U-joint utilizes a "centering ball" to keep things properly aligned. If the vacuum system is properly maintained, any time the truck is in 2WD, this shaft is only ever "along for the ride". If the hubs are left engaged for long periods of time without 4WD being selected, not only is the centering ball experiencing constant deflection, but the driveshaft spends much of it's time "whipping". Once the centering ball starts to deteriorate, it can self destruct in short order. And the resulting forces can cause the transfer case to virtually explode - something we do see on occasion - checking service history always shows that proper servicing has been neglected.... Have we seen rare failures? You bet - nothing is fool proof.... But, with proper scheduled maintenance, the SuperDuty ESOF is strong, reliable and trouble free... > At the transfer case end of the driveshaft to the front axle, there is a > double cardan U-joint. This U-joint utilizes a "centering ball" to keep [quoted text clipped - 7 lines] > something we do see on occasion - checking service history always shows > that proper servicing has been neglected.... If the centering ball is defective, there would be failure, but as long as it is maintained properly, it is OK to run it this way. This is how Jeep Wranglers, Cherokees, and older Grand Cherokees have been designed for years, without any way to disconnect the front hubs. In my experience, the centering ball would not fail without ample prior warning...squeaking, vibration...etc, unless defective. There is no maintenance that can be performed on the Ford centering ball... yes, it "should" give ample warning... but this has to be heeded to mean anything.... I have absolutely no experience with any sort of Jeep so I cannot comment on those.... As far as anything else is concerned... I am speaking from my own, personal experience. Without comparing this particular driveshaft to any other driveshafts, the centering ball can and has failed on the SuperDuty front driveshaft.... no amount of discussion can alter that fact.... I respectfully offer that I have worked in the automotive trades for nearly 40 years..... I have been with my current employer ( a mid-sized Ford dealer) for five years and I am currently shop foreman. Most of what we sell and service is the SuperDuty and most of those are diesel powered.... What I see is what I see and I can't go beyond that without getting in to conjecture.... Then it stands to reason the failed centering balls are defective, perhaps not receiving enough lube upon assembly. Jeep CV joints are of the same design and don't need hublocks to idle the driveshaft in 2wd, but yes, there have been rare failures in that case as well. And it is possible to re-lube them, it means disassembly of the joint, of course. What's your take on the OP saying two mechanics (one at a Ford dealer) said that you can't go more than 45mph if the hubs are locked? > There is no maintenance that can be performed on the Ford centering > ball... yes, it "should" give ample warning... but this has to be heeded [quoted text clipped - 12 lines] > powered.... What I see is what I see and I can't go beyond that without > getting in to conjecture.... Thanks for the info, Jim. I've hit every regular maintenance point with the vehicle, so if maintenance was missed then Ford dropped the ball. Not an impossibility. There was a vibration, but only a few seconds before things fell apart. The vibration was followed by a whine ("oops", foot of gas, looking to get off road), followed by the chaos of everything going to pieces. The truck had 51k, and front hubs were replaced about 43k. Spindle should have been taken care of at the same time. Who knows what else might have been going on in the transmission, crank-case, etc. that could have contributed. The CV joint had obviously blown, which was the start of the chain reaction. Rob >I see a lot of replies that are dropping the ball on this one.... SuperDuty >ESOF is a lot different from anything I have seen discussed.... [quoted text clipped - 106 lines] >> >> Rob (robs-f250@yahoo.com) > Thanks for the info, Jim. > The truck had 51k, and front hubs were replaced about 43k. Spindle should > have > been taken care of at the same time. "Hubs" were replaced at 43K, or "hublocks"? That is a different from the bearing assembly, which in the SD is a unit assembly, as opposed to a standard spindle-bearing setup. > Who knows what else might have been going on in the transmission, > crank-case, > etc. that could have contributed. The CV joint had obviously blown, which > was > the start of the chain reaction. How do you know that's where it started? If the CV shaft blew, it would disconnect from the transfer case, and bang around a bit. Explosion of the T case would easily destroy the CV joint in the front driveshaft. >> Who knows what else might have been going on in the transmission, >> crank-case, >> etc. that could have contributed. The CV joint had obviously blown, >> which was >> the start After re-reading your OP, you are calling the joint on the axle a CV joint. It is a U-joint. The joint on the transfer case end of the front driveshaft is a CV joint. No... the "CV" joint, in this case, is the double cardan U-joint at the transfer case front output flange... >>> Who knows what else might have been going on in the transmission, >>> crank-case, [quoted text clipped - 5 lines] > joint. It is a U-joint. The joint on the transfer case end of the front > driveshaft is a CV joint. Right. That's what I said. He called it a CV joint on the axle in the original post. There is no CV joint on the axle. > No... the "CV" joint, in this case, is the double cardan U-joint at the > transfer case front output flange... [quoted text clipped - 8 lines] >> joint. It is a U-joint. The joint on the transfer case end of the front >> driveshaft is a CV joint. >> Thanks for the info, Jim. > [quoted text clipped - 5 lines] >bearing assembly, which in the SD is a unit assembly, as opposed to a >standard spindle-bearing setup. Hubs. Almost $900 worth of Ford dealer charges. >> Who knows what else might have been going on in the transmission, >> crank-case, [quoted text clipped - 5 lines] >disconnect from the transfer case, and bang around a bit. Explosion of the T >case would easily destroy the CV joint in the front driveshaft. I guess *I* don't know that's where it started. The centering ball is destroyed (in the CV joint), and the mechanic told me that's what caused crank-case failure. One question, though. The mechanic told me it was the "crank-case", and the receipt says it was the crank-case. Isn't there BOTH a crank-case and a transfer-case? I should crawl under the thing and study it, I guess. :-) Rob > I see a lot of replies that are dropping the ball on this one.... SuperDuty > ESOF is a lot different from anything I have seen discussed.... [quoted text clipped - 108 lines] > > - Show quoted text - I have a 2004 Explorer with automatic 4WD and selector buttons on the dash for 4WD HI and 4WD LO; Also have a 97 Mazda B4000, 5-speed with dash mounted selector switch -- 2WD, 4WD HI, 4WD LO. Do I need to lubricate the front hubs as part of a normal service?? I do not run either of these vehicles off the road. Every six weeks or so I do take each of them out onto a rough local road with loose gravel and a steep up-grade, shift into 4WD HI and LO which I think is supposed to keep the hubs lubricated. During hunting season the Mazda takes a lot of trips on bad roads where I use 4WD HI and LO as needed. Thanks. Yours is quite a different system... It uses FWD style CV joints at the knuckles and the front diff - double offset at the knuckle and tripot at the diff (the reason is the tripots can "plunge" while double offsets cannot). Add that the intended use of the SuperDuty and your cars is very different as well.... As long as the CV boots are inspected regularly for deterioration or perforation, you should get many happy miles from your cars.... > Yours is quite a different system... It uses FWD style CV joints at the > knuckles and the front diff - double offset at the knuckle and tripot at the [quoted text clipped - 5 lines] > As long as the CV boots are inspected regularly for deterioration or > perforation, you should get many happy miles from your cars.... Thanks. I'll keep an eye on the CV boots. And -- I assume if I find one ripped or about to rip I pull the CV joint, clean it, re-grease it, and put on a new boot -- just like on my old swing-axle VW Beetles. >I had quite an experience coming home from vacation this year, and I'd like >as [quoted text clipped - 11 lines] > chunks > of metal flying all over I-80 in Wyoming. I don't really understand the sequence of events here. Where exactly was this joint that failed? If you were driving with one hub locked in, or two, forever, why would any universal joint fail? I don't see the connection. Does anybody see it? I have to assume that when you said crank case you really meant the transfer case. It's not easy to break that piece except maybe through failure of the frontmost u-joint. The joints inside the axle wouldn't explode anything if they broke. At least I don't see how. >>I had quite an experience coming home from vacation this year, and I'd like >>as [quoted text clipped - 21 lines] >frontmost u-joint. The joints inside the axle wouldn't explode anything if >they broke. At least I don't see how. My guess. He pulled his pontoon boat out of where it was parked / docked in 4x4 , then didn't take it out of 4x4 and flew down the highway. the t-case exploded and took a cv joint too. now he wants ford to pay Just to make it clear, the CV joint that failed is on the front drive axle, between two U-joints. There's supposed to be something like a little ball inside the CV joint, which was gone (only a little piece left). This resulted in severe vibration in the crank-case (attached to the front of the transmission), which caused it to fly apart. This resulted in the automatic transmission being destroyed. Apparently this all happened within a few minutes, as about 20 miles earlier when I was driving the pickup there was no vibration, nothing abnormal. My son was actually driving when everything fell apart. It was not in 4wd, as that causes REALLY bad binding when turning on dry pavement, and both my son and I are totally aware of what that feels like. The binding I've noticed all these years, when in 2wd, is very slight, and only when cranked all the way left or right. With the Warn manual hubs, as well as when the last set of auto hubs was brand new, there's absolutely no binding in a hard turn. I don't really recall if it did that brand new, but I don't think it did. Maybe mine experience is unusual. Certainly spewing pieces all over the highway is. It still wouldn't hurt for anyone with auto hubs to make a couple of hard turns in 2wd and make sure they're not binding. If they are, then it should be checked, no? Rob So it wasn't the fault of the hubs being locked, it was the CV joint in the front driveshaft that failed. Your experience is unusual. > Just to make it clear, the CV joint that failed is on the front drive > axle, [quoted text clipped - 33 lines] > > Rob > Just to make it clear, the CV joint that failed is on the front drive > axle, > between two U-joints. There's supposed to be something like a little ball > inside the CV joint, which was gone (only a little piece left). Let me clarify something here, Rob. Think hard about this. When modern-style 4 wheel drive vehicles first came out, they didn't have locking hubs. Jeeps didn't have that in WWII. Pickup trucks didn't have it in late 50's, the 60's and some of the 70's. Do you know what they had? Just a solid connection. You were expected to drive the vehicle 100,000 miles, or whatever it took to wear it out, with the hubs locked in and the front drivetrain rotating the whole way. Do you know what this damaged? Nothing. Just like the rear drivetrain rotating doesn't hurt anything. So whatever your situation was, the hubs have nothing to do with it. It is true that when a u-joint breaks, you can drop one end of a driveshaft on the road. If you do that, the driveshaft's rotation will probably hit something and that'll break all kinds of stuff. Wouldn't be unusual. With the front driveshaft, you have the option of stabbing it into the road and doing a bunch of damage that way. So basically you claim the root cause is a universal joint failure. It's still not clear where the joint is, but I'm going to guess you mean it was a double universal joint and is part of the front driveshaft. >I had quite an experience coming home from vacation this year, and I'd like >as [quoted text clipped - 14 lines] > it > might have been somebody's windshield. I think I agree with some other posters who suggested that you were in 4WD. That makes a lot more sense than your explanation. I don't think the hubs were at fault. The problem with your explanation is that you made it up. After your tranfer case broke open, you surveyed this pile of parts and then made up a series of events to explain it. Right? You need to think about this. If you know what failed first, you should certainly say so, but I so no reason to assume that you actually know what the root failure is. I didn't make anything up ... the transmission shop told me what happened. Now, that's not to say they couldn't be wrong about it, but when I first called and explained the vehicle and the failure, and asked what might have caused it, the mechanic told me they've seen many similar failures, and the hubs have always been stuck in locked position. Anyway, I don't really care *what* caused it, I still don't think parts flying all over a highway is an acceptable failure. Neither did the NTSB investigator (who referred my to NHTSA, since NTSB doesn't deal with auto issues). Y'all are free to believe I was in 4WD, but as I stated earlier, there's a distinct difference between the binding in turns I felt when NOT in 4wd and the binding when I had it in 4WD. Yes, I've occasionally forgot to take it out after pulling my boat, but the first turn I make it's *very* obvious. I made several leaving campground, as well as countless turns in the 100 miles before my son took over driving. He didn't touch it, and it wasn't in 4WD after the incident. Could there have been another failure that caused it to go into 4WD by itself? I suppose so, but my guess is that problem would still exist. Rob >I think I agree with some other posters who suggested that you were in 4WD. >That makes a lot more sense than your explanation. I don't think the hubs [quoted text clipped - 5 lines] >you know what failed first, you should certainly say so, but I so no reason >to assume that you actually know what the root failure is. >I had quite an experience coming home from vacation this year, and I'd like >as [quoted text clipped - 31 lines] > use some type of vacuum to disengage, and that's what people seems to > fail. As far as I know, the vacuum is used to engage the hubs, the hubs are spring loaded to unlock. In any case, by your description, you hubs have been locked for a very long time. The failure mode is more often that the hubs do not lock when asked, your experience is opposite that of most people with problems in this area. The result of your problem, exploding transfer case, is what I would expect though. (Your transfer case exploded, by the way, not the crank case.) Having said that, having the front hubs locked in 2WD would not harm the transfer case, transmission, or crank case.Lots of 4WD systems don't even have hub locks anymore, the front hubs are always locked and the 4WD system is engaged and disengaged solely by the selection of the transfer case. If the transfer case is not selected, the front tires merely turn the front drive shaft, but the front drive shaft is not connected to anything inside the t-case, therefore no damage is done. If your truck was being operated unknowingly in 4WD on pavement, then the tcase would explode. But, having the front hubs locked would not be an issue if the truck was really set to 2WD. (I've been operating my Jeep with the front hubs locked, and the tcase set to 2WD, for going on ten years, and there is no damage or ill effect of any kind.) Your complaint that there has been noticable binding in turns (I assume parking lot manuvers and the like) is a sign that your truck was in 4WD. The front and rear tires on your truck will travel different lines when making a turn in a parking lot (they travel different lines in any turn, but you will feel this in a parking lot more than on the road), and the binding you feel is the front tires scrubbing on the ground to release the stresses of the turn. The differentials accomodate the different arcs that the left and right tires travel in any turn, but the transfer case has no capacity to accomodate the different tracks of the front and rear tires. The result is that the transfer case gets stressed severely when the truck makes a tight turn on pavement. If the same turn was made on dirt or gravel, the front tires would slip on the ground and release the stresses, and you would not feel the binding that you felt on the pavement. Your truck is equipped with Part Time 4WD, this means it is intended to be used part time only, it should not ever be used where there is sufficient traction (dry pavement) to hold the tires from slipping on the ground. You ought not even drive you truck in 4WD in the rain, and unless snow and/or ice is covering the roadway where you are driving, you should not use 4WD at all when driving on the street. >As far as I know, the vacuum is used to engage the hubs, the hubs are spring >loaded to unlock. In any case, by your description, you hubs have been >locked for a very long time. So it would appear. >The result of your problem, exploding transfer case, is what I would expect >though. (Your transfer case exploded, by the way, not the crank case.) It's possible I got that wrong. I thought the crank-case was bolted onto the transmission, at the back end of the front axle, with the transfer case at the front end of the axle (I'm an expert on a few things, but not autos :-). What exploaded was what I thought was the crank-case (at the back of the front axle). >Having said that, having the front hubs locked in 2WD would not harm the >transfer case, transmission, or crank case.Lots of 4WD systems don't even >have hub locks anymore, the front hubs are always locked and the 4WD system >is engaged and disengaged solely by the selection of the transfer case. This is contrary to what the Ford mechanic told me. He said driving over 45mph with hubs locked, either set to lock or due to failure, would cause stress on the drive train, at least on my 2000 pickup. It's possible he's wrong, though. >Your truck is equipped with Part Time 4WD, this means it is intended to be >used part time only, it should not ever be used where there is sufficient >traction (dry pavement) to hold the tires from slipping on the ground. You >ought not even drive you truck in 4WD in the rain, and unless snow and/or >ice is covering the roadway where you are driving, you should not use 4WD at >all when driving on the street. Many replies I've read have said I must have been in 4wd, but I have no doubt it was set to 2wd. I'm pretty near certain that part wasn't broke, as the binding that occurs in 4wd is much more severe than what I'd noticed with hubs locked. > >As far as I know, the vacuum is used to engage the hubs, the hubs are > >spring [quoted text clipped - 9 lines] > It's possible I got that wrong. I thought the crank-case was bolted onto > the Not so. The crankcase is where the oil lives when the truck is parked, and where it pools while the engine is running, waiting to get sucked up by the oil pump to begin its journey through the motor once again. There is no immediate relation between the crank case and the parts that exploded. > transmission, at the back end of the front axle, with the transfer case at > the > front end of the axle (I'm an expert on a few things, but not autos :-). > What > exploaded was what I thought was the crank-case (at the back of the front > axle). Both the front and rear axles are connected to the transfer case via the respective drive shafts. >>Having said that, having the front hubs locked in 2WD would not harm the >>transfer case, transmission, or crank case.Lots of 4WD systems don't even [quoted text clipped - 8 lines] > the drive train, at least on my 2000 pickup. It's possible he's wrong, > though. I have to think you've gotten some terms confused. The t-case can only explode if it is engaged on the highway. Period. The front axle can be locked while the tcase in in 2WD, and no damage will result. >>Your truck is equipped with Part Time 4WD, this means it is intended to be >>used part time only, it should not ever be used where there is sufficient [quoted text clipped - 10 lines] > that occurs in 4wd is much more severe than what I'd noticed with hubs > locked. You _think_ it was set there, and there is a chance that you set it there, but in actuality, it was operating in 4WD when it blew. The front axle will not blow a transfer case set to operate in 2HI. I do not know how confusing the system may or may not be, my '95 Bronco had a similar system. You are suggesting that you selected 2HI, and if so, the transfer case did not respond to your selection. This does not change very much, you still have a t-case spread across central Colorado, but it narrows the problem set a bit. I am not prepared to engage in what you did right or wrong, but all that I know about 4WD systems, front hubs being locked in and of themselves can not cause the transfer case troubles you have reported. Your particular problem set can only come about if the transfer case was physically set to 4WD while on the highway, and this had to be the case for a very long time. My Jeep ('81 CJ5) has Detroit lockers on both the front and rear axles. I once (when I first bought it) pulled out of the dirt and onto the highway without selecting 2HI. With the variance is tire diameters on all 4 corners, as I approached 45ish MPH, my Jeep started to swerve all over the road. The cause of this was that the front and rear and the left and right were all going different speeds, and the traction on the roadway was fed back through the tires to the steering wheel. Your tcase did not explode because the front hubs were locked, it exploded because it was operating in 4WD. If you intended it to be in 4WD, you made a serious mistake. If you thought it was actually in 2WD, then your truck lied to you for a very long time. Me thinks that is a BS story full of holes. For one, even if you did not back up properly to disengage the autophubs, the only result would be the axles and front shaft would be turning and at the same speed as if they were engaged and being driven. mike >I had quite an experience coming home from vacation this year, and I'd like >as [quoted text clipped - 74 lines] > > Rob (robs-f250@yahoo.com) I still think he had just pulled the pontoon boat out of the water and had 4wd engaged from the loading ramp. Maybe he flipped the switch on the dash to 2wd, but the mechanical tension alone on the transfer case from the automatic transmission could have kept it engaged. > Me thinks that is a BS story full of holes. For one, even if you did not > back up properly to disengage the autophubs, the only result would be the [quoted text clipped - 83 lines] >> >> Rob (robs-f250@yahoo.com) |
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