Hi guys, Heres one from the past but I can't remember the outcome.

2000 cherokee went to the dealer for an oil pump problem. They pulled the oil pan, figured that it needed a new engine. Put the Jeep back together. And then called me.

I had them replace the engine.

After bringing it home and after about 300 miles, a thud started. When it started it was found under the drivers seat. This was a series of three small thuds in a row. This only happened when accelerating or decelerating.

Took it back to the dealer to confirm there was nothing left loose when they put the engine in. They told me it was the lower control arms.

Since the dealer was going to charge me $400 dollars to replace and the parts only cost $30, i did it myself.

This sound has not changed. It keeps getting worse.

Description- Thud sound around the floor board to the middle of the fire wall. Happens when acceleration, decelerating, shifting (automatic), occasionally when going over bumps. Has happened once or twice when sitting down on drivers side.

This almost sounds like a broken shock but I have checked.

Does not do it when the trans is in park and engine is rev'd up. Can not reproduce when rocking the jeep up and down or side to side. Does not happen when brakeing, just letting off the gas. Nothing is felt in the steering.

I was thinking upper control arms but I am tired of guessing. Anyone have this in the past?

Thanks for the help!

Try your transmission torque arm, it should have a couple of rubber bushings that can be worn out and as the motor accelerates or slows it can make a thumping sound.

Try inspecting the mounts summer,
Trans mount first then the engine mounts.

How would I check the trans torque arm? where is it? But no one feels it could be the upper control arms? Wow I was way off.