I noticed when it gets hot enough out or when I drive my XJR for an hour or so, I get a clunking from the rear upon load. So there's a slight clunk when I gas it and another clunk when I let it go.

Initially I figured it was the rear differential and had it swapped out with a Coventry West rebuilt one. The sound was still there. Could it be something else? Like rear wheel bearings? Shocks/suspension?

Nobody seems to know why this happens when it's warmed up either. Metal expansion?

 

It's always best to be reasonably certain where a failure is located before spending money on expensive new parts. There are a lot of joints and bushes on a Jaguar rear suspension, and it is necessary to check them out all round. It could even be an exhaust and its mounting, as this is a heat-up component. Other thing is the UJs; there are plenty of these around the rear end, although I am not sure if they are CV joints now. Other thing one can get is a slight clonk from worn splines where the drive shafts go into the wheel hubs. An XJR is a powerful car, and can wear things out quickly if driven on a "wheel-spin to wheel-lock" basis.

 

Thanks. The only reason I swapped the differential is because years ago I took it to the dealer and they diagnosed it to be a problem. I'm not that pessimistic on dealers to think they would want to con me out of potential $3,500 which I didn't elect to do anyway. Chances are they honestly either mis-diagnosed it or there is something else wrong now.

But anyway, what is done is done. Differentials are a known problem area anyway so it's not a total waste.

Thanks for the tips on the CV joints though. I will have to find a suspension guy.

I'd also welcome any other ideas. Thanks!

 

Check the rubber flex couplers at both ends of the propshaft (driveshaft in American) for cracks or deterioration. That can give you clunking under load.