Jack the rear end up wheels of the ground try to spin the wheel no spin take tire off pull brake hub inspect brake and e brake if ok there check bearing if ok there go to the chunk in middle of rear end pull pumpkin cover inspect gears and pin you should find one of those componets have failed locking it up
October, 31, 2012 AT 8:36 AM
Good suggestions but before you tear into the differential, and since it's not affecting the right wheel, the parking brake is a better possibility. If the cable is sticking partially-applied it will cause the leading shoe, (the one toward the front of the truck), to grab onto the drum. In fact it is only supposed to try to rotate with the drum to apply pressure to the bottom of the larger trailing shoe. A sticking parking brake cable is the most common cause of a locked brake going forward.
If I'm right, look at the cable where it comes out of the outer casing just a little ahead of that wheel. You'll see most of the cable is dirty or rusty. If the first 1/2" or so next to the end of the casing is shiny or looks different, it's not fully released. You may get it to release by flexing that casing if it isn't rusted too tight yet. The fix for that is replace that cable. Never think lubricating it will solve that.