I was wondering if some of you can help me out with this. Are pinion shims a must if you do a 2" drop to the rear?
Thanks for all the help.

 

If you mean just removing the factory 2" blocks from a 4WD rear to drop it to 2WD height ...
... NO shims needed, just shorter U-bolts or some spacers to go under the nuts (I chose new 2WD U-Bolts) because there is no change in pinion angle.

If dropping a truck an additional 2" with longer rear shackles, some packages come with the shims to correct the pinion angle. It's good to use them (shims) then because the longer shackles swing the rear of the spring up and change the angle of the axle and point the pinion down.

I have no desire to go lower with shackles, at 2WD height with blocks removed I have 4" over the axle to the snubbers.

 

If you don't shim the pumpkin is no longer at the correct angle. If you have a one piece drive shat it can cause a vibration and wear out ujoint, seal and bearing. Two piece driveshaft, not as likely. The shims are so cheap and so easy to install, why take the risk. I shimmed e ven with a two piece shaft and for 135,000 miles, no problem.

 

MY situation is a 2wd F150, using 2inch lowering shackles to level out the rear. I just heard of the shims today so I will be ordering them if they don't come with the kit. I appreciate all the help guys!

 

If you order Ground Force shackles, they come with shims. And yes, you should have shims with drop shackles because they do change the pinion angle.