Hi guys, well I have a new issue... On ce in a while I put it into reverse and I get a thump sound..Tranny or Differential? Also when I hit a bump in the road not always but some times there is also a thump sound...Any idea's?

 

I would look at shock mounts and subframe mounts.

 

I just started getting the same exact thing. I crawled under the car and looked at the shock mounts, which to look a bit worn but can't really tell if that is the source. My Jag mechanic is about an hour's drive away and he has already benefited from our X300 and XJS problems this year so I took it to a local Pepboys for an initial inspection/opinion. They said it might be the differential but they don't know for sure so they recommend taking it to the dealer. Well, I guess that means back to my independent Jag mechanic.

 

Hi Todd,

Unfortunately it's not really possible to inspect the rear shock top bushings without removing the shock/spring assemblies from the car and disassembling them. The bushes are mostly hidden by the upper mounting plate. If your bushings are more than say, 6 or 7 years old, they're probably due for renewal. If your shocks are tired you may want to consider renewing them also since you have to take the assembly apart to do the bushes. Other things to check are the Jurid flexible driveshaft coupling, the driveshaft center bearing, the rear engine/transmission mount, and the large rear subframe bushes that attach the lower differential mounting A-frame to the body.

Cheers,

Don

 

Thanks for the tip. Pepboys could not identify where it was coming from. They said it "could be" the differential, or U-joint but they don't know for sure. So, I picked the car up last night. When driving it home, it definitely sounded like it was in the left rear side and I heard it when turning left, up a hill, and sometimes over bumps.

The car has 94k miles and I know the front shock bushings were changed but don't think the rears were. The whole rear suspension could be original. So, I am probably due for a suspension overhaul.