I was driving the Jeep today on the interstate, then I noticed that when I reached speeds of 50 mph it started to act funny.
I got a har vibration in the rear only. I first I thought I had a flat tire or somthing like that. Has soon has I let go of the gas it went a away.
I played with a awhile, giving it gas then letting it go. The vibration went
away when I let go of the gas.

It only happend in about 4th gear.

After I drove for about 20 mins it went a away.

It seems to be shifting okay. It has fluid. No check engine light is on.

Could the tranny be going??

92 XJ 4.0L auto 4x4 85000miles. white color

 

Sounds like a u joint to me

 

really, will it make a noise?

 

i heard something like a clicking noise for a bit then it went away

 

Yeah. It could make a clicking noise sometimes. I almost garantee it's a u joint. Check an see if there is any play in them. Most likely it's the one on the rear end. It's a easy fix