transmission banging loudly

[littlejohn]

I'm out of state, so I'm going by word of mouth.
My dad was driving my Jeep on the interstate this afternoon in 5th gear when all of a sudden, it sounded like a machine gun. He shifted down into 4th and got off at the next exit. He got me on the phone and I could actually hear it making the banging noise, it was so loud.
I have the following clues:
1) It's doing it only when the transmission is in gear.
2) It does it whether the Jeep's rolling or standing still.
3) It sounds like it's sporadic (there's not a pattern to it and it randomly hits).
4) The "tempo" of it changes with the speed the Jeep is going.
It almost sounds like as the motor is spinning the transmission, something is slipping out of place and banging against something else.
Two weeks ago, I replaced the clutch and slave cylinder. Everything was torqued to spec and double checked. It ran perfectly fine up until tonight.
I'm thinking maybe my brand new clutch kit may have bit the dust somehow. I'm not ready to rule on that yet though, because my dad says that it's shifting just fine.
Any thoughts / ideas?

[mrclean]

Probably not a trans problem. If it were, it would not make noise when the vehicle was stopped and in gear. It could possibly be one of the pressure plate bolts backed out(not real likely if they were torqued properly. Also a good idea to use Loctite). Don't know what engine you have, but it's common for the 4.0's to get a stuck lifter, causing a machine-gun rapping noise. Post with more info and we'll try to help.

[Big-n-Broke-YJ]

i wouldn't rule out u-joints either....