Originally Posted by 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.
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...