2000 Cherokee 176K.
Actual lift is about 3.5" - 4".

I am going to use the IRO hack n tap kit and a front double cardigan driveshaft.
I need some sort of idea as far as where to start with shimming. Currently I have a 4 degree shim (OE driveshaft) and I get horrible driveline vibs.

Post a pic of the rear pinion angle.

Are they installed correctly? I have 4" of lift with 4* shims and no vibes.

With a double cardan joint, the pinion should be aimed directly at the output shaft of thr transfer case. I aim mine a couple of degrees down from there to account for pinion rise when under load.

^^^^^^^^this since you didn't install the HnT yet. Install it and then worry about angle since you wot know what you need until you proceed

How will installing the Hack n Tap change the transfercase angle?

And how would you determine the angle of the rear pinion is pointed at the transfercase shaft?

Im not sure if I have the right angle shim. I am trying to figure out what I need before I take it apart. Its my only car and I dont have alot of time to fuss with swapping shims like I am thinking I will have to do.

The 4 degree shim should work good with the hack-n-tap and 4" lift.
But will create bad vibes if used on a stock shaft/slip-yoke

I am pretty sure thats the angle shim I have right now. But I have the OE rear driveshaft.
Its aluminum though.
Im thinking it'd be a better idea to use a steel shim?

Double Cardigan



Double Cardan



When you install an SYE you need to shim the pinion so that it points at the transfer output case yoke. This is because the SYE allows you to use a double-cardan drive shaft. When running the OE single-cardan shaft, the two U joint angles must be identical.



Get your SYE in there and start messing with shims. Shims will get you nothing but vibrations with the stock shaft.