2001 Jeep XJ

Loud clunking/grinding sound when I accelerate

I have a loud clunking/grinding sound when I accelerate from a stopped position, especially when making a turn or going up a hill. It feels like it is coming from the front end and can feel it under floorboard. The sound goes away after getting up to speed. I have recently replaced the wheel bearings, tie rods, sway bar links and bushings, LCA bushings, and U Joints in front axle and rear drive shaft. CV joints in axle looked good. Also changed fluid in transfer case and both axles. Checked motor and trans mount, seem OK. Track Bar is solid, and shock mounts look good. Ball joints seem OK but are still a question mark, not sure if that would make this kind of noise. Really only run it in 2WD, running out of ideas.

 

Look here and check your engine and trans mounts.

 

On top of Cruisers suggestions, my exhaust hanger that sits next to the transmission mount had corroded and snapped causing a similar sounding noise.

 

I tried my best to inspect the transmission mount, from what I can see the rubber is good, took a crow bar and no wobble. However I did get a look at passenger motor mount, and although I tested the engine to confirm that there is some movement, but it's not much, does it look like it needs to be replaced ? The exhaust hanger looked good as well

 

https://www.google.com/search?rlz=1C...w=1120&bih=567

 

Took it into Meineke and explained the problem, had them check everything. They said u joints that were recently installed were binding , one on the front axle and one on the rear drive shaft, so paid them $500 to replace those again, they were not the main problem, grinding and clunking noise is even worse. They are now telling me where the rear drive shaft is connected to the transfer case is popping in and out, and punting since they don't service transmissions. Any advice before I head to the next mechanic?

 

If they actually said a ball joint on the rear drive shaft I'd ask them if they know what a ball joint is. 2 UJs (Universal joint) are the only joints on the propshaft. I don't know enough on the transfer case set-up to know how the shaft moves on it, I'm sure either the early or later one does move in/out of the case to compensate for axle movement but don't know enough to fully comment on it.

If you have the ability to do so, you could jack up the rear end and support it off the ground, chock the front wheels then put it in drive. If you hear the noise, it's on the rear end, if there's no noise then it'd be front or one of the mounts as Cruiser suggested. The best method is to get into the job and listen/look for your issues with noises like these. To test the front end in the same fashion you would need to disconnect the rear propshaft and stick it in 4WD. If memory serves me right, this can be done on the later transfer case which you should have but not the earlier as they'll throw fluid with the shaft removed.

 

My bad, meant u joint, not ball joint. I also took it to a transmission guy, he said something about a pin inside the transfer case holding the rear driveshaft in place that might be broken or loose but admittly he was not the shop expert and wants me to come back later. Now the rear drive shaft does move in and out from the transfer case as it is supposed to have some in and out play when driving, but mechanic #1 said the whole collar to the transfer case that holds the driveshaft in place is moving some as well, and didn't think that was supposed to happen. So if the problem is inside the transfer case guess my only option is another look by a transmission specialist, mechanic #1 is saying look into having tcase rebuilt. I am still wondering if I got a broken gear in one of the axles because don't have a lot of confidence in the diagnosis yet.. One other thing is we think the transmission mount is good, and engine mounts, and ball joints, and ujoints and tie rods , and CV joints in front axle all good at this point .

 

Where do you live?

Perhaps someone on this forum is nearby and can make a recommendation

 

Cincinnati Area

 

https://www.cherokeeforum.com/f39/

 

Resolved the issue, it was the output shaft gear in the transfer case.

 

Thanks for the update!

So the gear was worn/broken? Did they rebuild the transfer case or just replace the gear?

 

Rebuild, one of the parts was smoothed out on a grinder, not sure what the tranny guys did but it worked .