new leaf springs are changing differential angle

[aggiedave98]

I bought 2" lifted superlift springs for my suburban lift. Now, I'm getting driveline vibration. I'm convinced it's because the springs have a metal piece at the axle that looks like a doorstop. It angles the differential upward and makes it so the driveshaft is almost straight with the differential and therefore the u-joint is almost straight.

On the other hand, the upper u-joint by the carrier bearing is obviously at an angle.

From everything I've read, you need the same angle at both ujoints to cancel the vibration.

Why do the springs do that?? If they had a flat bottom instead of the "doorstop" shaped piece, I think it would be fine.

Do just the superlift springs do this? Do I have any options??

Thanks!

[cdowns]

i don't know much about lifted vehicles but can you just turn the springs around to reduce the angle??

[CrazyCooter]

My 8" skyjackers had a 4* wedge. I had to remove it because of the vibration.

If operating angle is any kind of issue for your truck, you could lower the transfer case to match the rear angle.

[aggiedave98]

I can't turn them around b/c they're 56" and the axle is offcenter. I thought of that though... actually I thought for a sec maybe I had them backward.

My truck is 2wd, so no transfer case, but to lower the tranny, I'd need to lower the crossmember for the tranny plus the carrier bearing crossmember and even at that, I still wouldn't have matching angles... I think removing that plate could do it, but that has the little dimple in it to fit into the axle.

[JIMs70GMC]

When you remove the degree shim you could get a new center bolt for the spring pack. The centering bolt is cheap a couple bucks a piece. When was the last time you changed the carrier bearing? The slightly lift could have accelerated wear on it. The blocks on both my trucks (2" and 4") are tapered, but I don't have a carrier bearing. You have 3 u-joints in your rear driveshaft and the carrier bearing, which shaft has 2 u-joints?

[Gunny]

while I do not have the experience yet with lifted suburbans, I do have a few years on Jeeps of which the Cherokee's are known for what is called the Death Wobble (vibs so bad that you can not hold the steering wheel straight) with lifts over 3 inches.

one way to get the drive shaft lined up right is to get a protractor and find what the measurements are (angle of the drive shaft at the u-joints) at the rear of the tranny and another at the front of the rear axle in stock form (if already lifted have someone with a stock set up let you measure thiers), after the lift is installed you take new measurements - this will let you know how much of a taper you need for some tapered shims that you would install on the axle.

depending on the size of the lift you may also need to lower the rear of the transmission and/or install a slip yoke eliminator.

Not sure if this is of any help if so and you need a little more info let me know.

Gunny

[8t5Silverado]

If the wedge is part of the spring, can you had another wedge to the other side to "cancel" out the first wedge?

[Sublvr72]

use shims to correct the angle