make sure to check the carrier bearing on you rear driveshaft. the rubber goes to crap after awhile, lift or not. replacements are around 60 bucks, and you can always permanently eliminate the problem with a one-piece shaft.

paul

Thanks Paul,

Most of the vibration is gone with the leaf bushings. As I mentioned in my last note, a small vesitige is left. When I get some more money, I will probably spring(excuse the pun) for new universals and a carrier bearing just because the truck has 155000 miles and these things don't last forever. Plus I have been in a vehicle that lost its driveshaft on the highway. Not fun.

Anyway, I thought I would give an update now that I have a few hundred miles: Since my last post I have been to "Vibration Hill", a hill that brings out the worst of the vibration and because of a curve makes you stay in the vibration's "sweet spot" for about 70 yards. While the vibration more noticable on the hill, it is nowhere near as bad as before on that hill, or anywhere esle for that matter. The problem is defnitely 80%-90% solved.

NCDiesel

Hi guys, just a bit of info, the maximum angle on a UJ for constant velocity is 27 degrees, anything over this and the UJ starts binding and will cause vibration and knocking in bad cases.

Did you notice any lateral or vertical movement with the gear stick under heavy torque? Worn rear mounts can cause probs with vibration etc.

Also, make very sure the UJ Yokes are in "phase"
They must line up along the length of the shaft through the sline joint. I use to run Toyota landcruisers (swb) and I got the back shaft out by one spline one day and it jumped around like a kangaroo.

If you are not sure about drive shaft balance, place a hose clamp around the centre of the shaft, The tightening screw acts as a balance weight and, if there is a balance prob, it should improve with the clamp in a certain position. ( rotate the clamp around the shaft a bit at a time).

The most common replacement bush here is Nolathane, These are designed to spin on the centre pin and you can get greasable shackle pins here for them. This allows the springs to flex more freely as they dont have to twist the normal rubber bush.

Another trick is to place a thin, high density Teflon slipper between the spring leaves, You can get these made up and they are also self lubricating and the differance these make to a leaf spring is amazing.

If you have a hanger bearing on the back shaft and the UJ angles are well within limits on the g/box side, drop the bearing mount down a bit, this will lessen the diff angle. The UJ on the g/box side only has to contend with mount flexing.

Hope the above has been of some help.

Cheers.