clays fx4

Got my bilstiens and 3 inch blocks installed today. The mechanic at the dealer said i will need to get drive shaft shims to stop the little vibration in the rear. Anyone else have this problem or is the dealer full of crap. only vibrates at slow speeds. Does it need time to settle? only 40 km on them. looks great though.

Seener84

I actually noticed this too, only when stopping at a light or sign. Light vibration from 5mph - 1mph. I don't notice it when driving or under throttle. I actually thought it was my new tires since I did everything at once. I would like to get rid of it though. I have 300 miles on mine and still does it, not sure how it would settle in...

DESERT_RACER

What lift do you have on the front end? What model truck, supercab supercrew single cab, what motor 4.2 4.6 5.4? And I cut my 4 inch blocks to 3 inch about 7 months ago and I have no vibrations. Now, did you cut yours or did you buy 3 inch blocks and install? If so, what brand? This all comes into play when trying to narrow down a vibration cause. If cut it could be because you cut them level, when in fact they have about a 5 degree angle cut on them and must match that after you cut them. Or could be because the hole you have to drill out wasn't perfectly straight or seated correctly in the block plate pin on your axle. If they were purchased, then start by checking the torque on your U bolt nuts. Torque is 90 ft lbs for a 2003 with 4.6 motor which is a 8.8 inch rear diff. 5.4 motor with 9.75 inch rear diff is same torque. If those are good, then I would check the new blocks to make sure they do have the angle in them. If that's okay, then check to make sure the blocks are facing the right way. Not to sound like a smart a@@ with that, but if the angle is not facing the correct way that can cause axle wrap or vibrations? Who knows. Hope this helped...

clays fx4

I got the procomp 3inch block kit. Got them installed at the dealer they are the rite way because the bump stop is in the rite spot. Went back talked with the mechanic today he said that i need the shim kit for the blocks to get the shaft angles rite. And i think hes rite because the blocks didnt have any noticeable slope to them. Went to napa auto parts and what do u know, procomp sells the matching shim kit for these blocks. Why these wouldnt be in the kit is beyond me.

clays fx4

Got new tires on today and retorqued the u bolts. No effect. I can c the angles these blocks are putting on the drive shaft . Ordered shims, will b here monday.

Seener84

I have the Procomp blocks too. They never mentioned a shim kit at 4 wheel parts. Would have been nice to do this once.

DESERT_RACER

Good to hear clay. So it was the angle in fact? Good stuff. Glad you got it fixed and let us know after you instal the shims how it works!!

clays fx4

Mechanic says only 30Min job. Trying to get it in monday rite after i pick up the parts.

Georgia FX4

Hi all. I have the same problem with my 5100 and Readylift 3" blocks. Would the Procomp shim kit work with my setup? I have the same vibration that I notice from 30mph on down. Goes away when the truck is in neutral though.

White-Out

Are they 2.5 degree shims? I have Raptor blocks and have the same vibration and figured I needed shims.