So I bought this all stock 2000 XJ, 97K, and replaced all the suspension parts, steering parts, front hubs, calipers/pads, drums, rear brake parts, wheels, tires, and exhaust. stock setup on suspension and full vehicle alignment. Everything ran sweet. Very fun truck and torque'y. A bit of a 75mph vibration, but I believe it to be tire balance,

I noticed the rear was lower than the front, so I decided to add a 2" shackle lift to the rear. NOW, its a vibrating mess. from about 10 to 40 mph. I hear differential chatter now when I let off, or give it gas. There was some backlash before when shifting from forward to reverse, but nothing to write home about.

Yesterday it drove beautifully. Today with new shackles, its a different vehicle. a serious disappointment. I also noticed a bit of rear axle play, in and out.. not side to side.

Is it possible the geometry of the rear and now also the front, could cause this? Im absolutely considering returning it to stock if this is how its going to act.

Any advice is appreciated.
Thank you,
Darryl

 

What you did (shackle lift) changed the angle of the rear driveshaft and the operating range of the u-joints in it.

It's likely the wear area they have been operating in is now different.

You also have changed the driveshaft angle enough that the front & rear angles no longer match (front & rear of the rear driveshaft).

Changing the u-joints in the rear driveshaft may get rid of some of it, depending on how bad the driveshaft angles are.

what is this differential chatter you talk about ??

 

 

Lube the splines where the driveshaft and transfer case meet.

 

I'll check the boot and lube the splines. good idea.

D