Make sure there is no play in the dogbone. It should have very little movement back and forth when it is in place. Also, move the wheel to completely stretch out and contract the suspension. Watch the dogbone and see how it is moving. I am guessing at one of the xtremes, the dogbone is moving too much in one of the cups. I had that problem with the ATX and I cut a short piece of fuel tube (maybe 1/8 inch) and put it in the cups where the dog bone fits into. One in the diff outdrive cup and one in the axle cup. This took out the extra movement and fixed my problem. Just make sure your suspension travel is still good afterwards and nothing is binding.