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Car Forum / Jaguar Cars / March 20061990 XJ40 Diff and box noises
Hi everybody im new to this game so here goes.... I recently bought my first Jaguar, after hankering after one for years. Drove it 300 miles from where I'd bought it to home. Car has certified LPG system fitted, single point injection type. There are 3 main problems Low compression on 4 and 5 (prob head gasket gone between cylinders? Is this common? I'm not to botherd about this as I've been working on classic sports cars for years (Lotus' etc) The second problem is the noise coming from the someware near the back of the car, sounds like a howling gail (swooshy type of noise!) from a distance and is audiuble from very low speeds under all acceleration conditions. I'm know these cars suffer from weak diffs, but is it just the bearings that go? Or does the crownwheel and pinion wear?. She's got 130k on the clock. The third prob is a vibration that occours when the car reaches 45-50mph and changes into top gear (sports box). Its quite bad, but as speed increases it lessens to nearly bearable at 90mph. I know the box locks up in top gear so that drive is transmitted without slip through the torque converter, could it be somthing to do with this part of the box? I've no experience with this type of box...HELP!!! Check for a radial tire with a seperating belt- I spent months on my 450SL looking for the noise I thought was rear end or wheel bearings until I put new tires on and it all disappeared. > Hi everybody im new to this game so here goes.... > [quoted text clipped - 24 lines] > with this part of the box? I've no experience with this type of > box...HELP!!! You'll find the cars differ; Lotus use rubber bands, jaguar have grunt A diff / wheel bearing noise would usually change with road speed and/or accel/descel > Hi everybody im new to this game so here goes.... > [quoted text clipped - 24 lines] > with this part of the box? I've no experience with this type of > box...HELP!!! I'm looking forward to the WALL OF TORQUE! Once the heads sorted, at the mo it wouldn't pull the skin off a rice pudding! Pretty sure its not wheel bearing as all is quiet under deceleration/coasting and cornering. Do diff bearing kits generally sort this type of sound as I wouldn't describe it as a whine, more a swirly windy noise which comes and goes with the accelerator? I know that sounds silly!! Got the wiff of EP diff oil the other day.... So its probably empty! Any thoughts on the nasty vibration I've got? I'll have a look on friday, get it on the ramps etc Some probable answers to your questions: 1. Low compression means you are most likely loosing the head gasket. VERY common problem for these cars stating at around 100,000 miles. While you are in there you should also put in seals on the exhaust valves. The AJ6 engine is canted at an angle so as it grows older it starts to "puff" blue smoke on start-up. Not a big deal and easily "fixed" when the head gasket is changed out. 2. Chances are VERY good that the differential bearings on the car are going/gone. Jaguar made a major mistake on the design of these bearings when they went from taper bearings to large ball bearings. Lift the rear of the car and slide under. Then, whilst watching where the axle goes into the differential, watch as a buddy "rocks" the tyre back and forth on the 6 and 12 o'clock position. If the stub axle bearing is the problem, you will see the axle moving in and out of the differential. Again this is a MOST common problem with these cars. 3. Finally, the chances are the shuddering is being caused by the Jurid connection on the end of the drive shaft. This is a big rubber donut that connects the drive shaft tot he differential flange. When they start to deteriorate, the drive shaft starts to slip off center and thus the "shudder" By The Way, chances are also that you will not be able to tell it is going by looking at it. Again, this is a VERY common problem with the XJ40. Everything you have mentioned are common problems and easily repaired with a bit of common sense and patience and a bit of money. Head gasket and related runs about $600 USD. Stub axle bearings and related run about $65 per side (do both sides) and I forget what the Jurid costs but I believe it is under $100. Cheers Webserve > Hi everybody im new to this game so here goes.... > [quoted text clipped - 24 lines] > with this part of the box? I've no experience with this type of > box...HELP!!! hiya, Looks like you'll be pulling the head off then, not tricky. Had the same sort of noise from the back end of my x300 and was told it would be the diff. Stuck it on the ramp and raised the back end, switched off the traction control and ran the speed up while the sucker, sorry, chief spanner twirler stood underneath and listened. Turned out to be a wheel bearing, which incidentally had no excess play in it at all to give away the fact that it was 4kt. Good luck with your 1st cat. m > hiya, > [quoted text clipped - 10 lines] > > m The vibration occurring at 50mph may be a drive shaft universal. These tend to seize after a while. Another common issue concerning driveline vibration is the transmission mount. These are notorious for getting weak and allowing the trans. to gyrate slightly. When you remove the cylinderhead look at the head surface closely as it is prone to decay if the coolant is not changed regularly. Sometimes the decay is so extensive you will need another head. The output shaft bearings have been talked about in this thread and is truly the typical culprit in rear ends, however the only true way to check them is to remove them from the side of the differential and physically check them. Rocking the tire back and forth may be misleading as I have seen many that were incorrectly shimmed and allowed the bearing to actually slide within the differetial case. Its almost like the assemblers had no standards. DieInterim Wow!, great responce from every one thanks alot for all the advice, I'll have a look at all these possibilities over the next few days. I'm still not convinced about the vibration though, as you can accelerate to any speed you like as long as the gearbox doesn't get into top, as soon as this happens i get the vibration. I'll enderver to locate it with your comments in mind. Cheers Mr smooth I had a look at the car over the weekend and tried to ID some of the probs. 1: The diff is plastered in oil and there are signs of it flinging out from the input and outputs, I put a small amount of oil in the diff (1/2 a pint was all i had) and this wasn't enough to fill it. I think its nearly empty! 2: Ran the car in D on stands and the noise from the diff was very loud. Its much louder on part throttle than full. Also the pitch of the main noise doesn't seem the vary with road speed. Then I tried spinning both wheels at the same time in N, one hand on each with my head by the diff and I could hear it then! Obviously at a reduced level. And I can tell the diff from the brake disc rub. Got my dad to give the wheels a rock @ the 1/2 12 position on both sides, small amount of movement on both, less than 1/2mm or 1/32inch. Of course if this 'is' bearing movement then they are knackerd. Very small amount of vertical play on the input shaft, nothing that a new seal couldn't cope with. I don't want to change the bearings to find that the diff is knackerd. This noise is bad , sounds like its grinding its self to bits.. I'll drain the oil and see if any bits come out. By the way it is NOT a power lock diff On to the vibration..... Is it something to do with the overdrive top?, At 54 mph the box changes gear and instantly there is a bad vibration, I can even see/feel it thru the steering wheel. The drop in RPM from 4th to ODrive is small around 200 RPM @ 2000RPM. Is this normal? Could this be sticky plates in the box? (No idea about autos). On the other hand I grabbed the tail of the box and pushed up pulled down, the box moved miles!(more than 20mm-3/4in) really easy/smooth with no damping. I know there is a spring and rubber isolators, so is this normal? There was no contact at any time when moving the box. Any thoughts? Or should I take it to the vets..... |
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