I found this in the Colorado forums:
http://www.coloradofans.com/viewtopi...ight=rear+lean
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Basically, you do the same trick that was done on S10s to level the rear. Since your right side sits higher than the left I will use your truck as an example.
If you want the right side to sit lower like the left side, use a floor jack to lift the right side of the axle until the tire is about 5"-6" off the ground compressing the right leaf spring. Then you loosen the upper and lower bolts on the right-rear shackle. You will notice the leaf and shacke shift a little. Then re-torque the bolts and lower the truck. The truck should be more even now.
If you want the left side to sit higher to match the right side then you lift the frame on the left side using a floor jack until the tire is just off the ground to extend the leaf pack. Loosen the left shackle bolts until the leaf shifts then re-torque and lower the truck.
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Two questions -
Could this apply in the same way to the H3? If the shackles adjust, it may be enough to level out the rear.
If this is worth trying, what is the torque required on these bolts?