1974 Chevy K20 Rear Differential Problem?

Reader Question I have a 1974 Chevy K20, 14 bolt open rear differential. I have replaced the axle bearings, seals, and fluid. No metal particles were found in old fluid. when i turn R. the inside or R tire spins at the same rate, as if there was a locker.. also when I back up and turn L. the L inside tire does the same thing… but neither seems to do it going the opposite direction. This started a week ago, and doing the above work had no effect on the condition.

please advise if possible… I don’t have a clue. thanks.

Hi there

I am assuming you have a POSI Trac rear end. I would visit your local GM dealership parts department and buy a bottle of Posi trac additive and add It to the rear end. You will need to drive it awhile for the additive to do anything. You can make some BIG figure 8’s in a shopping mall parking lot to help get the additive into the clutches. I am betting you have a clutch that is stuck and the additive it made just for that reason.

If that does not do the trick, you might have a worn out pinion gear or something wrong with the pinion.

Blessings,

Austin Davis