I've tried searching and cannot seem to find a solution so any help here is greatly appreciated. 1999 Cherokee (4.0 AW4 and NP231 D30/C8.25) makes a grinding noise when accelerating in reverse only. No noise when moving forward. I've checked u-joints and all fluids are full and new. Jeep has made the same noise for about a year and just recently became more obvious. Thank you all in advance.

Might just need to adjust the shifter linkage.

Check motor mounts and transfer case mount...look closely at the exhaust there.