Okay, I was running around a bit earlier and traffic ahead of me stopped suddenly (not lockup suddenly), but my rear end did just that. It locked up for about 2-3 seconds then there was a loud pop and then the truck stopped. It's done that one other time, but that was on wet pavement so i thought it was just me. This time dry and I was going about 25mph when I put the brakes on. This is after about two weeks of getting the rear vibrationslowing downat highway speed (50-70mph). Anyone else have the rear do this on more than one or two occasions?

 

sounds like the springs on the shoes are not releasing while brakeng. the sensor is suppose to let the springs compress and retract under heavy braking. might be why the system is going into lock up mode. then the force of the truck is snapping the system free.