Rear end hot rim to rim...
Eazy Zilla, not everyone is the contributing type so you always run the risk of side tracks being built.
Question, did the shop that rebuilt the rear leave out the axle thust buttons, which is advisable to do when switching to greens. If they left them in and the button to shaft end clearance is tight allready (lets say .005") then that amount can be taken up easily by axle axial growth from normal driving generated heat. If the clearance is zero then the shafts butt against each other putting excessive side load on the greens and getting everything hotter than hell fast. To test the theory I'd grab the passenger side axle bearing housing and since it should be the threaded housing, remove the lock and back the housing out of the rear end 1 full turn then run her for that 15 minutes. Or you can have Mark check it out and tell him I said hello.
Terry