Hey y'all!
So for awhile now, I've been experiencing grinding noises from my 2001 Jeep Grand Cherokee 4.0L.
The grinding happens mostly once my engine gets warmed up, and sounds like it is coming from under the vehicle, and I can feel it from under my feet. The grinding happens once I drive for a bit and grinds at idle and acceleration. One thing I want to put out there is that my exhaust (more towards the muffler) is loose. I did bring it in and they said my exhaust was loose towards the front and was hitting the drive shaft, in which was causing some signs of scraping. There are signs of scraping.
So after bringing it in, I got it "fixed" or how I would put it "reduced" to the point where it would barely if not make any grinding noise at all, but I would feel it grind again if I drove it 50+ miles. Now it is to the point that if I drive 5-10 miles, I feel it way more! But two or three weeks of getting it "fixed" the problem continued to where it was previously. One thing I want to point out is that it doesn't grind in neutral or park, and again only does it when the vehicle is warmed up. I also did notice that it is much severe when I'm on a hill.

Any suggestions to what might be my issue? Or what I can do to fix this problem? let me know y'all!!

 

Another thing I would like to point out is that there's a clunking noise also going over bumps, but I think that is due to the loose exhaust.

 

Seems like the exhaust system likely shifted back to where it is making contact with the driveline. I would take it back and have them look again for a proper fix. I am not familiar with the layout on the Grand Cherokee but you may have a missing or loose collector to down pipe bolt or rusted out flange, loose connection at the catalytic converter, broken or missing hanger, fit problem due to incorrect part or other exhaust system integrity issue. It you have clunking due to some part of the exhaust system hitting something you definately should get that corrected. Note that as the system heats up the pipes will expand and potentially push things out of alignment if not properly supported.