My "new to me" XJ has a Iron Rock 4" short arm lift. The prior owner installed it around 1 year/8k miles ago.

It's an automatic 4.0 with a little over 200k on it. Limited trim level.

It has what feels like a driveline shudder/vibration between approx 20-37 mph.

I have tried manually shifting it and also accelerated quickly and the vibration is there regardless of engine speed or gear.

After about 40mph it's very smooth and will cruise on the highway at 70-75 without an issue.

I tried different wheel/tire combos and the driveshafts & motor/tranny mounts seam fine

Any idea's or thoughts?

Thanks in advance

 

Just wanted to add this XJ has a 242 transfer case.

Is it possible it needs an SYE? Also, would most people upgrade the 242 with the SYE or go to a 231 w/sye?

Thanks

 

I have a vibration at those speeds. What was the fix?

 

Possible the front or rear drive shaft angle is too great, or the lift caused excessive wear in either the U-joints or slip yokes (or the CV joint on front driveshaft ...if there is one).

Eliminate tires or a bent rim as a possible vibration source.


Nice looking rig!

 

At 250K, the front u-joint on the rear shaft was toast. Changed them out with two Spicer 1310x. Sometimes the answer is simple and just what you would expect.