my lift kit only came with an add-a-leaf and new coils. a guy who installs lifts said that 2001 cherokees have a transfer case that requires shiming the rear axle with a three inch lift. im having someone in a machine shop make me some shims but im curios how they work. im pretty sure they go between the leaf and axle but how do you know that their in the right spot. more than anything i just wanna know how they work cause i hate working with somthing and not knowing how it dose what it dose.

 

H I dropped my Tcase and used 4 degree shims on my 4 3/4 inch lift and have no vibrations. The way they work is they straighten out the angle of the pinion (Drive Shaft) so that there are no vibrations or binding of U joints...Tj

 

They tip your axle back a little bit so the pinion is pointed more towards the transfer case. Helps with driveline vibes. Most people don't need them on a 3" lift though. Better option would be an SYE