Hey guys. This is my first post, and i really hope somebody will help me. I'm 21 and I drive my Cherokee sport back and forth 80 miles to school every week. I've owned it about 5 months and the whole time the wheel bearing has moaned. After I put on the skyjacker 3 inch lift and 31's, the diff made a terrible noise every time I would let off the throttle and let it coast. So I went to the scrap yard and bought what looked like a VERY good condition D35. I wanted a Chrysler 8.25 bad, but they had about a dozen cherokees, all with D35's.

To put a long story short, I've put the new axle in, and the constant moan is gone, but it still makes a load "rump rump" banging kind of noise when I let off the throttle and let it coast. I put 2 degree Bar Wedges in to help the driveshaft angle, but the noise is still bad. I've checked the U-joints and they seem fine. Is it the pinion bearing? If so, the scrap yard will replace it for free, but how do I make sure to get a good one this time? Somebody please help me. I gotta get this thing going by sunday. Any input will be GREATLY appreciated. Thanks in advance.

 

Sounds kind of like backlash in the differential. I just swapped in a D44 with a Aussie locker and when I am coasting the differential groans a bit. The Aussie instructions said there may be more backlash with their locker so I am not that concerned. When on the gas it goes away completely. I did need to drop the transfer case half an inch by using nuts as spacers because when braking the angle of the diff would cause the u-joints to bind a bit as I also installed a RC 3" LIFT. Once the add a leaf sags a bit I plan on removing the spacers from the transfer case mount bracket.

 

Why don't you take it to a shop and have them check the u-joints. I'll bet one or more of the back ones is bad and the rump rump you hear has gotten worse since the lift. From your post I wasn't sure if you had that sound before the lift coupled with the groaning sound or not...
Mike