Rear driveshaft angle

[jbleguin]

PO put on what looks like a 4.5" lift on the Jeep. They did drop the tranny and Transfer Case but didn't consider changing the location of the perches to get the driveline angle in a better spot. As you can see it is at a 30 degree angle. I am getting a clunking noise at all speeds and was hoping that shims and a CV shaft would help. Any idea on what size shims to use?

 

[Torxhead]

I would suggest removing the Transfer Case drop, installing a CV joint and set the pinion angle direct to the driveshaft angle. This would require a reweld to the axle mounting pads. Up front would require the same thing plus rotating the axle "C"s. You should not need a CV joint.

 

[jp360cj]

What's and angle of the tcase output and rear axle input? The angle of the driveshaft itself isn't really relevant to any vibration or issue. What matters is the operating angle of the u joint. If you can't get the ujoint angles below 18 degrees or so, then you'll need a double cardan (CV) driveshaft for the rear.

If you go the CV route, then might as well ditch the tcase drop. As mentioned, the rear axle will need to be rotated to point at (or 1 degree below) the Transfer Case output. The best way to do this is by cutting and rewelding the perches. No need to do anything with the front. The lower front output and longer front driveshaft mean the front u join angles are much better than the rear.