Drive line clunk... WTH?

[prcjeep]

Okay so the Specs
96 4.0HO
AX-15 5 speed
NP231 from pre96(has rear cone)
dana 30 front (ds currently not installed)
C 8.25 rear

Okay so I have this clunk i feel in the floor/seat when I left off the accelerator. The jerk associated with it makes a loud noise as well as the jolt I can feel. Its only one clunk. It happens in forward and reverse and in any gear. It doesnt happen everytime.
I checked the ujoints in the rear ds and they appear good and have been changed within the last 5-6 thousand miles.
Name my problem :)

Or ask questions for more info, I dont know what it is. Only thing that i can think is maybe tcase chain.

[4.3LXJ]

Check your shock mounts. This is a fairly common problem that usually ends up being bad shock bushings or loose bolts.

[prcjeep]

shock mounts as in the gas shocks? or as in leafs and coils?

Ive been trying to drive more economically and not have huge power transitions from accel to coast and brake etc. to avoid the jolt/noise. I just want to know if I should be prepared for my t-case to fall off or trans to blow up or anything else severe lol but hopefully fix it before that happens

[4.3LXJ]

shock mounts as in the gas shocks? or as in leafs and coils?

As in the place the rear shocks bolt to the body and the bushings involved

[prcjeep]

As in the place the rear shocks bolt to the body and the bushings involved

Gotcha... I havent looked at those since I put the lift on back in Feb.

[bluedragon436]

I would look into checking all your bolts for tightness.. especially at the rear end.. should do it every now and again... especially after a lift install, and wheeling.. although most people don't.. myself included.. I had a clunk when I first start off in either direction... always only did it one direction... but after installing the lift.. didn't have it... then it started doing after roughly 3k miles after the lift install.. got it up on the lift the other day and hit all the bolts with the impact gun... no more clunk for me.. so I would check into that...

[prcjeep]

ok will do... after driving it home tonight it really feels like its drive line related. Too dark for anything looking tonight.

My tcase crossmember has a crack on the outter layer. could this cause anything related? Its been cracked for 4 or 5 months

[bigjim350]

It probably is your crossmember or a bad tranny mount.

[prcjeep]

argh... well guess I should swap out my cracked one with the good one i have in the 'boot'...

[msmoorenburg]

argh... well guess I should swap out my cracked one with the good one i have in the 'boot'...

sounds like a plan :rolleyes:

[Firemanray]

I'm with BigJim on this. It could be a motor mount also.

[prcjeep]

Wel Ive got an update...

My tcase had zero fluid in it... not even water. I think it all leaked out of the front output shaft seal since i sheared it off... So as for the noise, I guess its safe to say it was the chain?? slipping??

[prcjeep]

sounds like a plan :rolleyes:


Soo I attemped to swap out my t-case cross member but that was not successful, The mount surface was different than my original and was acting as lift to the t-case, I think it had something to do with mine being a manual trans

[bluedragon436]

Yeah the stock crossmember for the manual trans does have a roughly 1" drop to it.. with little to no loss of ground clearance.. that is why folks like me that are running a TC drop look for the manual XJ's in the JY's to grab the crossmember..

[prcjeep]

well this clunk has turned into more of a grinding/binding noise... and I hope its only coming from my toasted tcase... I have the 5 speed ax15, could my tranny be making these noises? It happens weather in nueatral or going into or if I'm coasting...

[bigjim350]

Yes your tranny could make that sound, but more than likely its your t-case.

[prcjeep]

never updated this tread but for anyone researching... it ended up being only my t-case, I swapped it out for a used one from the local pick-a-part