make sure that the rear cvd's are set correctly... they have a tendency to bind up if they are not spaced correctly... I hope you have the rubber o ring installed in the diff cups.. they help.. the other thing is after alot of jumping, the cvd can work its way loose and start to come out of the drive cup.. if it does, the torque of the engine will instantly break the shaft... you can adjust the spacing of the cvd by using the pillow ball screws to adjust the play..... Its funny today I broke my right rear cvd for the first time in quite a while...