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Car Forum / Ford / Ford Trucks / March 200693 Ranger 4L A4LD transmission hesitates..vacuum?
At a stop, I have to rev my engine either in neutral and shift into drive to get the tranny to engage, or rev it in drive and try to let off the gas before it slams into 1st. Then it misses the shift into 2nd until I either do the reving thing again, or wait about 4 seconds for it to shift on its own. I had a tranny shop replace the modulator, and that helped for an hour (apparently there was some fluid in the vacuum line). I know I have a crack in some hose in the top of my gas tank for two reasons....one, it will not pass the emissions vacuum test, and two, the one time I topped off my tank leaked from what appeared to be above the tank for a cupful. So, I am wondering, if not having proper vacuum in the gas tank can be causing my transmission vacuum problem, and possibly slight performance problems. The problem has gotten slowly worse, but I do not drive much. If I drive for half hour the shifting problem sometimes goes away. Advice? > At a stop, I have to rev my engine either in neutral and shift into > drive to get the tranny to engage, or rev it in drive and try to let [quoted text clipped - 10 lines] > has gotten slowly worse, but I do not drive much. If I drive for half > hour the shifting problem sometimes goes away. Advice? Sounds like a failing transmission to me. Even with no vacuum, it should engage without reving the engine. > At a stop, I have to rev my engine either in neutral and shift into > drive to get the tranny to engage, or rev it in drive and try to let [quoted text clipped - 10 lines] > has gotten slowly worse, but I do not drive much. If I drive for half > hour the shifting problem sometimes goes away. Advice? I have the same transmission in a '91 Explorer. I've had good luck adding Lucas Transmission Fix. I've already had the trans replaced once. I also had a leak on my fill tube going to the gas tank. After a little investigation I found a hole in the rubber hose and patched it. It did not, however, effect the performance of my Explorer. > At a stop, I have to rev my engine either in neutral and shift into > drive to get the tranny to engage, or rev it in drive and try to let [quoted text clipped - 10 lines] > has gotten slowly worse, but I do not drive much. If I drive for half > hour the shifting problem sometimes goes away. Advice? Ok after doing some research. I see that your transmission uses a standard simpson gear set which means that it sounds like your pump is having some issues. The 1st gear issue would be slow application of the front clutch pack, and the second gear issue would be slow application of the rear servo. This means that you probably have low line pressures or your transmission needs rebuilt badly. I would take it to your local tranny shop and tell them you are still having the issue, and see if they have a way to dyno test your transmission. This way they can control the load and see the line pressures as the transmission runs. It will also give them clutch and servo apply times to help diagnose what is going on. On that note, transmissions are very tricky to diagnose, and I am by far no expert, and without a clutch apply chart to tell me what is applying and what is releasing then I cant say for sure what is going on in there. But it does sound like the synch on this transmission is all out of wack. Pk My problem continues. I don't know crap about cars, but I now believe I may have three issues converging to cause poor A4LD performance. First, I think my vacuum system is somehow compromised, causing the vacuum diaphram to perform poorly. It is my assumption that by revving the engine, I build vacuum and allow any small vacuum leak problem or transmission fluid in the vacuum modulator line to be cleared. Somehow there may be a leak or blockage in the vacuum block on the engine that all the lines are connected to, or a crack in a vacuum line effecting all vacuum performance? As mentioned before, I also know there is a crack in some line coming out of the top on my gas tank because once when I toped off gas came out from above the tank (apparently from there at least). Second, my engine is not performing optimally for unknown reasons....may need a tune, could be the vacuum, but last week I added some fuel injector and carb cleaner and have been using premium gas, and I notice a slight increase in performance. But, after I drive for half an hour, the shifting problem pretty much goes away. Also, last week I loaded a 300 lb anvil in the rear of my truck bed, and performance seemed to improve on the drive home. So I thought maybe whatever recognizes load (computerized?) may be at fault. And finally, while I am driving in fourth gear at over 40 I hear a slight whirring while accelerating, which goes away when I let off the gas, which is either the tranny or a vacuum leak. > > At a stop, I have to rev my engine either in neutral and shift into > > drive to get the tranny to engage, or rev it in drive and try to let [quoted text clipped - 27 lines] > > Pk DLC, Since you are self proclaimed novice on cars. I would STRONGLY suggest you take your car to a shop and let someone else diagnose the issue. If the shop is NOT test driving your car before they start diagnosis, then you need to take it to someone else. Also, if they are not fully listening to your complaint, take it somewhere else. There are 2 parts to a good technician. 1. that he listens to the customer fully, and 2. that he knows his trade and is ASE certified for the issue that you are complaining about. If you think you have a vacuum leak, then you can find it by cutting off a piece of hose (3/8" diameter should work fine) and put one end up to your ear and move the other end around the engine while it is running. You will hear what sounds like a slight whistle or air rushing through a small hole, that is your vacuum leak. Use a piece of tape to mark the vacuum leaks as you find them, then turn the vehicle off, and fix the leaks, ONE AT A TIME. Replace the hoses/Tees as necessary till you have fixed all the leaks, and then start the vehicle back up and see if you have fixed all the leaks. The leak on the top of your fuel tank sounds to me like the vacuum like that hooks up to the carbon canister. This canister is supposed to neutralize all the fumes in the air being pulled from the gas tank, if this is leaking, that can also cause a vacuum leak. I hope this helps, but again I urge you to take it to a shop, this sounds like it might be over your head because of the transmission issues. They are complex, and hard to diagnose. PK > My problem continues. I don't know crap about cars, but I now believe > I may have three issues converging to cause poor A4LD performance. [quoted text clipped - 56 lines] >> >> Pk |
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