[CC69Rat]

Some of the other guys do too I'm sure, but I hang out on this site alot.

http://www.nastyz28.com/forum/showthread.php?p=2468039

Check out this article on the Pinion angle. What happens is this, when the truck is lowered, the springs change blocks added etc. The Axle orientation in the truck barely changes.

If you take a look at the front pinion, where your driveshaft connects to your rear end housing. This is what I'm referring to. And the fact you have a two piece driveshaft just complicates it a little more for you. (you have more angles to contend with) Not the end of the world, but you'll see what I mean.

All the angles where the trans tailshaft meets the first part of the driveshaft (A) then where driveshaft 1 meets driveshaft 2 (B) and where driveshaft 2 meets the rear end housing (C) You want these angles to be fairly close in relation. this article will explain it much better than I could type it all out.

The way I think about it is a jump rope. When it swings, the top angle of each handle causes a shorter distance on the inside than it does the outside. Make sense? So when the driveshaft spins (as you speed up) the vibes get stronger and stronger. Slow down and they go away.

It really sounds like (to me) if you put some pinion angle shims under your rear axle housing and 'nose down' the (C) point I mentioned above it would really help you. I would almost bet the yoke on the rear end housing is pointing slightly 'up' in relation to the (C) driveshaft.

This is really common in lowered trucks, and lifted Jeeps (I have been around the Jeeps too)

Just for example if you put a couple washers under the tailshaft of the transmission and the mount to raise it up just a hair, it might take 1 deg of angle out of your driveshaft in relation to point (B)

You don't want these completely 'Zero'ed' out .. but 1deg or two at the junctions will really help with high speed vibes.

I dropped an S10 ext cab and it has the carrier bearing in it too. I had t ouse a kit that moved the tailshaft of the trans and the carrier bearing to make this angle straight.

Here's their kit. I know this is S10 stuff we're talking about .. but this will explain the situation very well.

http://www.jagsthatrun.com/Pages/Par...aft-Align.html

Get this right and your truck will ride sooo much better. I promise.