I feel your pain and I have read the thread several times now.
It eats rear u joints-it should not eat u joints-that maybe the end result of what the real problem is.
Have you re-torqued the u bolts?
Have you inspected the springs for a bad bushing, cracked leaf etc.
Did you put the car on jack stands under the lca's and rear axle at ride attitude & plot the ctr pt of each wheel on the floor using a plumb-bob to see how "square" your wheels are? Uh-oh I am giving away secrets now...
