I have a 99 XJ with a 3.5 Rubicon Express lift. There is some vibration and want to know which would be better a transfer case drop or using pinion shims.

If you have an auto AW4, you can stick the crossmember out of a 5 speed manual in it, and lower the TC, 3/4" w/o losing any ground clearance. Get ahold of XJWONDERS, in the selling section. He has em !!! I'd try this first ?

With my 3.5" lift, I noticed about a 1/4" of new metal extending out of the transfer case tailhousing as seen on the slip yoke. I dropped my cross member by 1" with 2 pieces of 1" square tubing drilled on the same spacing as the crossmember for each side. Removed the studs, purchased longer bolts and put it all back together. The slip yoke was back at the original place and I have no drive line vibrations. I didn't do anything with pinion angle shims.

Either plan should be considered a temporary fix with best plan being a SYE.

All that being said, a 3.5" lift normally is actually more like 4-41/2" initially and settles back in after a while in the 3-31/2" lift. If that holds true, a temporary fix maybe adequate to fix a short term problem and can be removed after the suspension settles.

Happy Jeepin'
TexasTaz38

I appreciate the help!!!

best bang for your buck is the manual crossmember swap to your auto trans if you indeed have a automatic

Rusty's has a 1" drop more durable Trail Tested Crossmember: Part # RA-CM2000-XJ
http://www.rustysoffroad.com/jeep-sk...rop-28812.html

I do have an automatic transmission. Will I need anything besides just the cross member from a vehicle with a standard transmission?

My RE 3.5 inch lift ended up requiring a SYE and a transfer case drop along with new drive line. You should be able to use a front drive shaft for this.

A SYE is not to be used in conjunction with a transfer case drop.. A SYE/ CV-driveshaft along with proper axle shims for rear axle angle is the way to go. Trans drop is a band-aid for ones not running a SYE.
A transmission drop also adds extra strain on motor mounts.

When I first put my lift on I had vibes as well. Because there are so many variables as to how much TC drop is needed to cure the vibes I decided to do a variable drop. I went down to Ace and bought longer bolts for the cross member and a box of washers. I stacked the washers for a 3/4" drop and drove it. Still had vibes but considerably less. Added more washers for 1" drop and vibes be gone. Ended up wrapping the washer stacks with black vinyl tape to aid in installation and improve aesthetics. Like Dumajones said, " Trans drop is a band-aid for ones not running a SYE. " Plenty of info out there as to why that is true. I was messing around with the lift height so my TC was temporary. Eventually I installed a proper SYE with shims.

I would advise anything but axle shims, even a T-case drop.

Pinion shims should be avoided at all cost.

Besides cutting and welding in axle perch to new location.
How would you get axle pinion angle without shims?

Can you explain why?