Liberty proshifted trans popping out of gear

well didn't solve the tranny popping out of gear problem, but found out my Duster hooks well enough/has enough power to blow up something in my rear end when i launched at 4200 RPM. egads........have to get it opened up and see if it was the gears or the posi unit, if gears then i guess Dana 60 time as I 'had' new Richmond gears and the posi is new Auburn. sheesh, fun and games with slicks!