Ok so here's what's happened and is happening:
About 6 months ago I was driving onto a main road by what seemed to be an intersection, but what turned out to be a really high curb and gave the underside of my Jeep a good smack. Ever since then under acceleration it makes a noise that sounds like my fan is hitting something. The motor and transmisson mounts have been replaced via suggestion by mechanic. The noise can be heard under any acceleration faster than that of a grandma. Any ideas? Our next guess was the fan shroud, as we have been through two of those already.

 

Does it happen under load, or engine speed? Meaning if you left it in park and raised rpms to 2-3k or wherever you hear the noise, is the noise made? Check the shroud, check the electric fan clearance to the power steering pump. Check the fender liners havent come loose and are hitting the wheel when you get enough wind under them.

Sent from my htc evo on the Cherokee Forum app. I haz teh technologiez

 

Had the same thing happen to me it was the bottom section of the fan shroud (clutch fan) the tab that kept the bottom plastic hooked to the radiator snapped out somehow.

 

It would make sound when accelerating because the fan would suck it in and hit it.

 

If I held the brake and riased RPMs it would rev and sound good, lett off the brake and shoot forward. That's when I hear the sound.

 

Sounds like the driveshft may be hitting something or you knocked your exhaust pipe loose and it's hitting something.

 

Open the hood and have a friend watch the engine bay while u power-brake the Jeep. Of course have him/her on the side so u don't run em over.
C what u can c at that point. Sounds like it may be lifting under power= twisting up or to the side.

 

Found out.it was the.fan clutch and replaced it. Not been a problem since