Sometimes over bumps on street but the thump is much less.

 

I was wondering about control arm bushings as well. Is there anyway to check and see if they are worn before replacing them??

Can you reproduce the thump in the driveway? I have not been able to do it

Chuck

 

check your ball joints too. But yeah getting someone to turn the wheels with your eyes on all the connections really helps. You'll be surprised what's messed up down there sometimes.

 

If you can feel it under your left foot, it's definitely the upper ball joint on your track bar.

 

What would be the symptoms if the ball joints go bad, or if the control arm bushings are going??

is there any way i can check them in the driveway to see if they are bad or not before I throw a parts grenade at the axle/knuckle??

I cant speak for the OP on this, but when I got my XJ over a year ago I had this thump that we are discussing. I climbed under the XJ and every one of my TRE's were shot, including the one on frame side of the track bar. All have been replaced, drag link, tie rod, and all the ends. New track bar, new shocks, new coils. The sound was the same both before and after. All nuts/bolts torqued to haynes spec.

For a while I was convinced it was my sway bar rubbing because I put a lift on the jeep (links too short), but when I removed that, I still got the noise.

My running theories are ball joints or control arm bushings, I just cant seem to replicate the noise in my driveway. I have had my head under the front of that thing a dozen times with my wife/kids turning the wheel
chuck

 

Have you checked the front bolt on the leaf spring? I had my passenger one work out part way and shear. Before I noticed it, it would give a thump sound on that side as the leaf eye would move up and down, hitting the floor.

 

I just found the upper mount on my adjustable track bar just loose enough to cause the thump.I got about three quarter turn on it. no more thump. Thanks for the input all.

 

Joe,

thats awesome. I was feeling like I was jacking your thread. This damn thump has been driving me nuts for months!!!

I know my track bar is good, and my TRE's are fine, all replaced within the last 6 months

Tomorrow I am gonna get the jeep in the garage, get the wheel off the ground, and see what I can find out.

Chuck

 

mdcmn7, these were the issues I had when I bought my 99 about 8 months ago. I had a thump at low speeds stopping and turning . My swaybar mounts were worn and contacting frame. Replaced all better. Next I had a thump and noise in floor when i accelerate and stopped. 99 and newer I am not sure about 98, Have a boot on the rear driveshaft input shaft all the lube was dried up. removed packed grease into the splines noise gone. When I did my lift and was replacing my track bar you can see how much load is on this bar if there is wear in either end I would think it could cause the same noise. Good luck, I know its a pain tracking these down. Now I have a leak in my radiator. It never ends.

 

it really is a pain to find random bumps/thumps. When I replaced my track bar I also replaced all the hardware on the mounting bracket. It was all garbage. I am leaning toward my ball joints. The jeep has almost 100k on it, I guarantee they were never changed, and all of my other steering components were all worn pretty bad, so it would make sense

 

If anyone cares, I found my ball joints were shot, AND I had added a front skid plate from an older XJ. Everytime I turned left my draglink rubbed against the skid plate and my ball joints thumped.

New ball joints, and skid trimmed... thump solved

chuck