So basically, I lifted my 2001 XJ with a 4" a few months back. Also some new 33 in tires. However, and its kind of hard to describe, the rear diff now has a cranking (?) noise when I go uphill and accelerate from stop. Cranking is the best word to describe it as. Kind of a few short clicks that I can feel. It's weird. Does anyone have any info on this?

 

It's probably a driveline vibe from the new driveshaft angle. Have you installed a SYE or transfer case drop? Also might be a good idea to check if your driveshaft u-joints are in good shape and have no play.

 

Yeah, the driveshaft U-Joints are fine. No SYE, but I did do a transfer case drop.

 

when you gas it the rear leaf springs wrap and then the ujoint flanges bang together is goin to be my guess . get someone to get in it and put it in gear and hold the brake have them give it some gas as if they wer going to power brake it and do a burnout wile they do that get down but not under the jeep and watch what happens it is amazing how much stuff moves form the torque of a 4.0

 

Late reply, thanks for the tips

 

Sounds like your rear axle needs some shims to get it right, or you need to change the amount of your t-case drop.

You say under normal driving, you don't hear it.............but, when you accelerate or climb a hill, the extra force needed to get the vehicle moving, or climb the hill, means the springs give a little bit more than during normal driving, and the pinion moves just a tad bit more, and that is when you hear the noise.....high load/high torque situations.