Greetings all, On my 2002 XK8 I have developed a clunk at low speed accelarating and braking for instance when going over speed bumps etc. I have tried to find any play in the driveshafts and bushes all seem OK. There is some play in the drivers side diff. output bearing, would this be the cause? It is the same side as the clunk is coming from. If it is this is it an expensive job to replace the bearing?

 

A worn diff bearing is usually accompanied by oil weeping from the seal. It's not something that clunks unless it's very seriously worn. It's also a rare failure.

For a 'clunk', I'd be looking at the inner and outer half shaft Universal Joints (this would account for noise when accelerating/braking) and/or worn bushes of which there are plenty of possible culprits on the rear suspension mounting frame (which would account for noise when going over speed bumps).

Graham

 

I had the same kind of noise in my xj8. After many trips under the car and even tying a gopro camera to the under side to watch for movement, I finally found a bad rear transmission mount gone bad. Replaced it with a new one from car quest and the noise is gone. I would have sworn it was the rear end. hope this helps.

 

Thanks a lot, your answer is very helpful because I have the same issue as you. However could you tell us what the real transmission mount gone bad was or some picture about that? Thaks in advance.

Angel

 

I went under the car with a pry bar and pried up the rear of the transmission. The mount is located at the back of the trans on the bottom. It is a round can shaped thing with a bar in cased in rubber in the middle. The bar should be firmly seated in the rubber. Mine had about 1/2" play up and down and the bar was just resting in the hole. It made a clunk when I accelerated or decelerated at low speed or over a bump. Found the mount at Carquest auto for the same price as on line (around $157). Made a real difference in the sound and feel of the car. Sorry I didn't take pics.

 

Thanks a lot Stevee, I´ll try it. Could you remember the id of the mount at Craquest Auto or specific link. This would be another great help to locate the issue

Angel

 

If its not that mount you're looking at, it could also be the rear, lower shock bushing. Me, and others, have spent a long time trying to diagnose such a sound. The rear of the car being jacked up off the ground won't work to hear it...its being 'pulled' by the shock. With the rear of the car lifted and on stands (don't forget to wheel chock your front tires!) place the jack under the tire and lift it till its within the normal range of travel of the shock, hit upward on the bottom of the shock with a rubber mallet. That's how I found it.

 

^that's dedication. Nice job.

 

Thanks for all the pointers to my rear end clunk. Should the weather get above freezing then will try all your tips. Will let you know what it is (eventually). Other Jag. jobs to fit in-on other Jag!

 

Ayup, I believe this was my issue as well. I also had a broken trans mount that was replaced just last week, and voila, no more clunk (that also sounded like it was from the rear driver's side).

 

Thanks Sentinelist, could you tell the id of the mount that you was replaced or any other clue to locate it?

 

I just had this fixed on mine. Same sort of noise you described. It was the bushing. All better now.

 

lower schock bushing is the most common source for rear "clunks" like discribed. and they look like in pretty much good condition while already gone bad.