Here goes. I installed the belltech 2" rear drop shackles on my Supercrew. Well at 30mph down to 20mph i get a vibration since my pinion angle has changed. Belltech guy informed me i needed shims. So i bought the shims. They come in a box along with a long bolt and nut. Well, not knowing what the nut and bolt was for, i went ahead and started installing the shims. I loosen the u-bolts hold the axel and put the shims, fat part of the shim facing the front like Mr. belltech guy said to and tighten everything down.
Well, on the test drive the vibration got worse!! WTF!! I'm about to put the factory shackles back on and forget it all!!!!!!!!!!!!!!!!

Help

 

I just did the 4 inch drop in the rear on mine. And i had to put the 6 degree shim in mine. There was a small steel shim allready there on the bottom of the leaf pack when i tried to put all back together the u blots werent long enough untill i took the small metal one out and only put the shim in but all is well now.

 

hmm, maybe i'm supposed to remove that factory shim and bolt and nut and replace them with the new shims i got. I just assumed that i just slide the shim in between the factory shim and axel and that would solve the problem.

I hear that factory bolt and nut holding the leaf stack together are a bear to get off!

 

yes you do need to take the center bolt out of the leaf pack. hold the leaf pack together with some c clamps and if the bolt is rusted on just grind the nut completly off and drive the bolt through the bottom. and replace with the bolt that come with your kit

 

Cool. It'll have to wait till this weekend. Gotta put work the rest of the week.

Thanks for the help ScrewOnBudnik20!!