Transmission Tunnel Noise / Clunk

The06LJ

Member
Supporting Member
Joined
Sep 1, 2021
Messages
42
Location
LINY
I am at my wits end here with a noise/clunk. For the last few thousand miles i have felt something moving around under my Jeep. being 15 years old, i assumed (correctly) that basically everything was worn out and that when done with its rehab, the noise would be gone. it is not.

First of all, its felt more than heard, and its felt right next to my right foot, in the transmission tunnel. it seems to only happen when the jeep is well warmed up, after at least 15 miles of driving. It doesn't happen when stopped, or under hard acceleration, or during shifting. Basically just while cruising. seems unrelated to engine speed, gear, steering, or clutch position.

so its a 2006 LJ 6 speed, ~100k on the clock, and everything downstream of the T-Case is brand spanking new. After the axles and driveshafts were done, and the noise, didn't go away, and possibly got worse, i figured maybe my T-Case linkage was flopping around, but i put the jeep up on a lift and nope, its tight. as is *Everything* else. The thing drives like its brand new, and everything seems perfect. closest i found was a loose heat shield over the exhaust, for which i added a washer and secured that.

I'm losing my damn mind. any ideas, before I load the parts cannon with a new transmission and T-Case?
 
First of all, its felt more than heard, and its felt right next to my right foot, in the transmission tunnel. it seems to only happen when the jeep is well warmed up, after at least 15 miles of driving. It doesn't happen when stopped, or under hard acceleration, or during shifting. Basically just while cruising. seems unrelated to engine speed, gear, steering, or clutch position.
"Felt more than heard" and only when "well warmed up" and "just while cruising" are interesting symptoms.

When you had it on a lift was the engine running at full operating temperature and was the Jeep in gear to act as if it was cruising?

I know it may sound crazy but I don't think I'm the only person to ever have my Jeep on 4 jack stands with the engine running, the transmission in gear, the transfer case in 4wd and both axles locked. FWIW, I may be crazy but I bet I'm not alone.

I'm losing my damn mind. any ideas, before I load the parts cannon with a new transmission and T-Case?
Don't fire that cannon yet. That's a ton of $$$ and maybe too soon.
 
My transmission mount was torn in two, but I couldn't tell be just looking at it.
It would thud and clunk in the trans tunnel but also cause a knock at my feet . I don't know just throwing ideas at you
 
  • Like
Reactions: The06LJ
"Felt more than heard" and only when "well warmed up" and "just while cruising" are interesting symptoms.

When you had it on a lift was the engine running at full operating temperature and was the Jeep in gear to act as if it was cruising?

I know it may sound crazy but I don't think I'm the only person to ever have my Jeep on 4 jack stands with the engine running, the transmission in gear, the transfer case in 4wd and both axles locked. FWIW, I may be crazy but I bet I'm not alone.


Don't fire that cannon yet. That's a ton of $$$ and maybe too soon.

It was cold and off. The timing of getting it up to temp and then right onto a rack is difficult.

Only thing stopping me from firing the cannon is that I'm currently planning an LS and 6L80 swap. So putting in a new AX15 to just take it out in a few months is wasteful in a way that I cannot justify. I can't speed up the swap and I can't trust this thing as it is.

Rustygastank has an interesting idea of it being the mount. I may throw a trans mount at it. Maybe what I take out is shot.
 
It was cold and off. The timing of getting it up to temp and then right onto a rack is difficult.

Only thing stopping me from firing the cannon is that I'm currently planning an LS and 6L80 swap. So putting in a new AX15 to just take it out in a few months is wasteful in a way that I cannot justify. I can't speed up the swap and I can't trust this thing as it is.

Rustygastank has an interesting idea of it being the mount. I may throw a trans mount at it. Maybe what I take out is shot.
I would start with trans and motor mounts. Although it would be odd that they don’t present noise during shifting.
 
I havent driven it yet, but this is the trans mount i pulled out. i think there is a good chance this is what i was feeling. I'm more than a little surprised that in the way the symptoms presented.

20220128_160459.jpg