Shim question without SYE

I'm sitting at about 4.5" of lift in the back with an 8.25 rearend. I have a 1' transfer case drop, but would like to lose it and just shim the rearend. I have very little vibes right now and have about 25,000 miles on this settup. No u-joint problems at all. Should I just leave it alone, or could I shim enough and lose the transfer case drop? I did search and it seems that even some people with an SYE and shims still have vibes! My XJ is a 99' and origonaly without the TC drop I had horrible vibes. Any succsess stories about shimming and stock driveshafts? :repair:

snow drifter said:

I have very little vibes right now

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Vibes no matter how minute are bad.It will be even worse w/o the TC drop,get a SYE kit!

RCP phx, thanks for the reply but I was looking for a little more than "get an SYE" I can't justify spended 300 to $400 on an SYE. I live in the mountains of CO. and have acess to numerous trails.The stock drivetrain has seen many many 4x4 trips, including 2 trips to Moab with no ill effects. I mistyped in my post, I have 35,000 miles on this settup. "minute vibes" included. I just wanted to lose the TC drop, If the shims don't work, I'll just leave it alone.

leave it alone if your not gonna get an sye. shims are the wrong thing to do. with a stock setup you want the output of the t-case and axle to be parallel, only with a sye do you want the pinion to be pointing at the t-case

With single u-joints on each end of the driveshaft you want u-joint cancellation that is within 1 degree and operating angles not greater than 3 degrees.
Measure the output yoke angle (A) at U-joint end cap installed in the yoke.
Measure the input yoke angle (B) at the u-joint end cap on the pinion yoke.
measure the drive shaft angle at either end (C) U-joint end cap installed in the drive shaft.
Subtract A from C (C-A) to get Transmission output operating angle.
Subtract B from C (C-B) to get input operating angle.
U-joint cancellation should be within 1 degree. Acheiving this by lowering the T-case or shimming the rear axle is in my opion no different.
However if you shim the rear over 3 degrees you need to keep in mind lubrication for the pinion bearing.
Getting operating angles below 3 degrees is hard with a lifted vehicle. That's why most go to a SYE and double cardan style drive shaft.
Vibrations in the drive line, while hard on the t-case and pinion bearings, most often just shorten the life of the U-joints in the drive shaft.
You didn't say why you wanted to get rid of the t-case drop. If it's a clearance issue, Rusty's sells a cross member that lowers the t-case 1 inch with out loss of ground clearance.
You did say you're vibrations are not that bad. If it ain't broke?

Daffy XJ Big Thanks! That's the answer I was looking for. With 31's and no plans for bigger tires in the near future, I thought I would lose the TC drop to gain a little more clearance underneath. But your right, If it aint broke... I'll look into that rustys skid. Thanks again. :cheers: