Transmission clunk... throwing parts isn't working! (Jeep Wrangler)

[hillstrubl]

Hi Everybody, I was wondering if any of you might know what I should try next... I have a 1998 Wrangler that I built for offroading in college that my dad has been driving around (read: not really driving, it has sat a LOT for the last few years) as his weekend toy. We're looking to sell it but I noticed a new "clunk" when releasing the clutch, sometimes. It feels/sounds like something is binding up then popping free and it appears to be coming from the transmission.

Parts so far-
-The rear u-joints/centering ball of the front driveshaft had wear so we replaced it with a new Tom woods shaft (slightly less clunk)
-Transmission mount was the original one, replaced it (was cracked-ish, but probably was ok) (slightly less clunk)

It happens when releasing the clutch at nearly any speed, but more prominent at lower speeds/gears.
I can reduce it to almost never if I drive like my grandma, but 1 or 2 will still sneak in on a short drive.

1 friend thinks it's the throw-out or pilot bearing another thinks it's another mount that is bad (engine mount possibly). Other than this which is definitely bad, it shifts fine.
I'm going to try changing the fluid with hope that what comes out is very obviously bad (prob 12 year old fluid).

Transmission is a NV3500 out of a ~03 Wrangler (not original) swapped in probably 10,000 miles ago and has been fine until this.

 

[hillstrubl]

Update, did some more diagnosis today. I don't believe its an engine mount as we jacked it up from the engine and didn't see a broken one, nor did it overly flex where a crack would be in the rubber section if that was the case. I did find some slop in the rear driveshaft when in neutral. As the clunk feels like something is binding up then releasing, I had an idea. What if the fluid is degraded/low/bad in the rear diff and the limited slip that's in there is the culprit? When taking off its binding up then releasing? Would that be violent enough to call it a clunk? I'm going to change the diff fluid (and make sure to add the limited slip additive) then report back. If that isn't it, the next 2 possibilities are T-case/T-case output shaft or the transmission itself.

(Ford 8.8 rear axle with a limited slip out of a mustang)

 

[hillstrubl]

I think I found the culprit(s)... Rear trackbar bushes are totally gone, at a sit still its "solid" but with any real effort you can move it around. What appears to be happening is the bolt is pushed to one side of the mount (without functioning bushes) upon takeoff, but then when shifting or torque is otherwise not holding it there, it slams the other side of the mount, providing said clunk. Also one of the front axle u-joints is pretty bad adding to overall noise, but I believe the trackbar is the culprit.

 

[acheck]

sounds like typical jeep problems. those suspensions don't last at all.

 

[hillstrubl]

In its defense its 22 years old and has sat MUCH more than its been driven for the last 7 or 8 of those years. I just hope this is the issue