Auto Transmission Problems on '96 XJ

I believe my transmission is starting to have a knock when cold. At first it sounded like my front u-joint was bad (been down that road before and replaced the front drivers side u-joint last Summer). This just started a couple of days back... and I noticed it after replacing my motor mounts this past weekend. At first I thought perhaps one of my mounts was loose (not the case) or that my tranny mount was bad (haven't changed that out yet). It makes sort of a klunk.. klunk.. klunk.. sound similar to what my front U-joint used to make when turning (before I replaced that) It doesn't do it when excelerating in a straight line and I feel no slippage.

... then I got to thinking back about 2 months ago, I changed the tranny fluid and when doing my checks it appeared that I was over-ful by about 1/2 a quart. I never got back to removing fluid as I was rushed during the job. Could I have fried my tranny by running a little too much fluid? During the fluid change I simply drained the tranny via the plug and didn't pull the pan off. Seems like it took about 2 quarts on the change and that's why I wasn't sure if my dip-stick was just off, or if indeed I did overfill. I know adding too much engine oil is a bad thing, but does it work the same on transmissions?

Is there any easy way to diagnose a bad transmission, or do you have to take them apart? Perhaps I'm not even looking in the right place as I've never had a tranny go bad on me and don't know what they do when they go bad.

Any suggestions are appreciated.

I doubt a bad transmission would make a klunk.. klunk.. klunk sound. Usually the first thing is shifting problems.
I would look at the front or rear drive shaft or the transfer case first.

Would the transfer case make that noise even if I'm not in 4wd? I may have to get under the Jeep and have my wife start it up and see if it makes the noise... because it does for a very quick time when starting up cold.

just stuff you wife under it and you start it up. lol

unless you killed your u-joints again i dont think the t-case would do that.

You sure its not your exhaust pipes hitting on something?

Follow-up...

I'm not sure what this is. I have checked almost everything I can think of, don't see anything busted and the tranny shifts and functions fine. It almost sounds like a rattling sound, like something is hitting the frame or parts are hitting at certain times. I wonder if I have a busted front shock. I have some Monroe SensiTrak shocks w/about 45K miles, but haven't seen any oil leaks from them. I may just need to remove and check. My exhaust seems to be snugged pretty well (installed the Rusty's Flowmaster Cat-back about 10K miles back and it seems to be holding up well).

I also greased up the front driveshaft slip yoke this past weekend as I thought that may be it, but still had the same rattling (albeit less) this morning. It seems to be more noticeable when starting up and driving when the Jeep is still cold, or after sitting for a while.

Any other suggestions? I'll keep updating when I figure this one out.

I've had a similar clunk up front. I can't locate where it's coming from either. When I first bought my Jeep a couple months back I had a totally blown out upper shock bushing and the shock was rattling all around. It made a similar sound. You might want to try checking that the top shock nuts are tight if you haven't already.

Other suggestions I've heard for front end clunks include the trackbar-could be loose on the axle or frame mount...I've also heard people talk about wheel bearings going bad. try jacking up the front end with the truck totally cold and see if you can wiggle the top of the tire in & out. If it wobbles at all you could have bad bearings...

Then of course there are ball joints. I don't know a really good way to check them, but they can clunk if they're worn out too...

Welcome to the clunk club!

Have you checked the fluid level in the T-Case? Also the catalytic converter will rattle when bad.

Follow-up..

Replaced the Transmission mount this past weekend and it appears that was my problem. The old mount that I removed w/pretty weak and flexible, but wasn't split. The new one was much better and it appears to have fixed the rattle/clank noise I was experiencing.


Thanks all for the information and checks.

sure is a nice thing when you find a repair is easy to get done and not too expensive. good job!!