Suspension/Driveline angle question

[thearborbarber]

I have had the lift done for a couple of weeks now. I got under and measure my drive line angles. The TC is 6 degrees, the drive shaft at 12 degrees and the diff at 16 degrees. I have a small vibration from 25-30mph. My question is; in the picture below you can that rough country has a shim bolted in place at the bottom of the spring pack. What are your guys opinion on taking the shim out? I am guessing that will bring the pinion angle back down closer to the TC's.

 

[chulisohombre]

It looks like with the spring pack you have it would tilt the pinion down too far without it. You can try it and see what happens. Looks like a 6 degree. Might make angles a little closer. You have to get the axle u joint within 2 degrees of the transfer case joint. So you would need more like a 2 degree shim or a zero rate at 4 degrees cut if you need a inch in the rear. I know some trucks stink bug in the rear even with a lift spring.

 

[thearborbarber]

The first picture wasn't taken very level giving the impression that it would point down. Here is a shot of the pinion angle. It points up quite a bit. That's why i was thinking taking the shim out out would work.

 

[chulisohombre]

It does point up quite a bit in that pick. It's hard to say how Much more it comes up under torque when the springs load up. I'd try it but from the angles you have would need a 2-4 degree less shim to make the angle better. So it will be close without it and may help you out with the vibe. Or move the vibe to a different speed. Are you sure the ujoints are good and lubed and the driveshaft isn't tweaked? That would cause the same issues.

 

[thearborbarber]

The joints have 5000 miles on them and feel tight. I didn't have the vibe before the lift.

 

[warwgn]

Yep you need more down angle on that diff for sure, I say ditch the angle shim.

 

[chulisohombre]

Yep ditch it and see if its better. Mines about like yours and have no issues. Every truck is different though.