Solved - Rumble & Squeak

[Tob]

The NV3550 in my TJ developed a terrible sound recently. It started as a slight squeaky chattering under acceleration at highway speeds about a week ago. It has progressed to a dry, low rumble with the same chattering squeaks. The sound only happens under load, accelerating or engine braking, and at any speed. It completely goes away at any speed when I disengage the clutch. The rumble gets louder and deeper with increasing RPMs. I don't have a video but I may have to take one to help identify the issue.

I recently went through a pretty deep water crossing, but I don't know if that is related to the issue.

This is my daily driver and I would appreciate your help in diagnosing the issue so that I can get it back on the road ASAP. Thanks!

 

[Tob]

Bump!

Is it possible that the transmission fluid is contaminated from submerging in water? Should I try changing the fluid? Or is the transmission already toast?

Surely someone here has done a deep water crossing in a manual and knows what could happen…

 

[Tob]

Just to resolve the thread, the rear driveshaft turned out to be the culprit. I guess the double cardan needs some attention. I was convinced it was the transmission or transfer case because it made no noise or vibration even while rolling if the clutch was disengaged.
Many thanks for the helpful input.

 

[Andy-WhiteTJ]

Glad you got it fixed and reported the solution.

 

[sab]

Glad you got it fixed and reported the solution.

Ditto! This site gets better and better every time a solution is posted afterwards!