LostInTheWoods

So, this has been going on for a while, but it usually quiets down during the winter months. But summer’s here and now it’s back and louder.

I keep hearing this clacking grinding noise coming from the transmission tunnel. Part of the problem is there’s not really any consistencies with it. It’s there when my Jeep starts up from cold, stays around for a while then vanishes once everything warms up. Then it returns when moving at slow speeds (parking lot speeds), sometimes during acceleration, and sometimes during braking.

My friend thinks it’s the transfer case chain being stretched and worn out. I also read that it could be a worn out U-joint. No idea which it is or if it’s something worse than those, but I can tell you that it’s coming from the front end of the transmission tunnel.

Thanks for the help,
-LostInTheWoods

LostInTheWoods

Update:
So the sound went away… again.

I probably should’ve mentioned it comes and goes often. Most times it happens for a day and then leaves for several months before it comes back.

Still don’t have a clue what causes it, but I’d like to finally get it fixed.

lawsoncl

Is it the exhaust chattering against the cross member? Usually due to a worn out transmission mount and/or engine mounts.

LostInTheWoods

So I was driving a bit more and I went over a pretty big pothole and that caused the sound to come back. I definitely think it has to be either the U-joints or this. I'll have to check tomorrow, but I feel that I'm narrowing it down.

cruiser54

I wouldn't rule out lawsoncl's advice. U-joints don't ever quiet down once they get noisy.

LostInTheWoods

Update:
Checked the exhaust and crossmember and they’re fine. I have about a quarter inch of clearance between them.

I also checked the U-joints and they seem to be fine. There isn’t any excessive play and the sound hasn’t returned.

I did find a video and this is pretty close to what the grinding noise sounded like:

The owner of the video stated that it was caused by a bad slip yoke, and I have no idea how or if it can be repaired or replaced.

awg

I dont think 1/4" is enough clearance

With the slip yoke, might depend on the TX case type

I seem to recall with my NP242, just yank the rear driveshaft out and lube it, it might even have a grease nipple ?

cruiser54

1/4" isn't enough.