Hi,
Have a 1992 f150 5 speed 6 cylinder..having problem with rear axlew..almost seems like the rear brake is locking up.took of wheel and turned the drum..turns ok bu then suddenly locks up on occasion..can reverse direction and will continue to turn till locks up again.not sure if it is a posi track axle..anyone hev any ideas?
u-joint seems to have been solid with no noises.
thanks..

 

if youre sure the brakes arent locking than I would pull the cover off the diff and take a look at the gears (spiders, side gears, ring and pinion) as well as the center pin. sounds like something is busted in there.