Adam Rogers

I have a 98 xj 2WD when I'm in reverse with the wheel turned all the way to the right I get a thud or a clunk from the right rear also I get similar thuds and clunks coming from the front right and left while making sharp turns ... from what I've heard it's probably my U-joints but does anyone have any other ideas or experiences with what it could be?

PatHenry

Sounds like U-joints... It might be just the front, but the rear driveshaft is pretty easy to look at (and take out) to check. If it's clunking, you'll be able to see the movement in the joints. The fronts are a little harder to visually see and get your hands on, but it's not too tough.. U-joints should have zero play when twisted and once they fail to the point of clunking are real obvious with the amount of movement.

The front left and right are likely both axle joints. The rear sound may actually be the front joints, but very possibly the rear driveshaft. It's unlikely the front shaft is in play, but it's also easy enough to crawl under and twist by hand just to see if you can move anything manually. For ALL u-joints, If it moves manually (in a way not obviously "proper") then it's bad and needs to be replaced. I like to hold one side steady and try to twist the other side to see if it moves at all... it shouldn't.

Other clunking possibilities are:
- Exhaust pipe on crossmember. Check that there is visible light between the pipe and the crossmember, if it's touching, it's not right. I put a brand new "stock" exhaust on my 95 3 years ago and already the hanger pieces have rusted off both at the rear and at the crossmember.... there is a hanger welded to the front pipe (the one between the manifold/header and catalytic converter) that hooks into a bracket on the transmission mount/crossmember.
- Shocks. The top front mounting points are not very sturdy and these Jeeps are old and rust prone. The bottom is beefier, but also known to rust out in places that salt the roads in winter.
- Sway bar bushings - Both the links as well as the sway bar to frame bushings are known to wear out with the age of the XJ (this year marks the 20th anniversary of the last model year for the XJ.. so all of them are AT LEAST 20 years old at this point.)
- Suspension wear - this is less likely to clunk as to give vibe and death wobble, but it's possible and easy to DIY inspect... if it's bad enough to clunk it'll be super obvious.
EDIT --- Check your leaf springs on the reverse clunk.... bad leaf springs can clunk like you're describing and MUST be fixed immediately... it's a safety concern!!

If it is, as most probably the case, bad u-joints and you want to do the u-joint replacement yourself, search the threads for my instructions/tips for a deep description and advice from someone who always dreaded/feared u-joint replacement to make your life as easy as possible.