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Ford 9" differential clutch pack

1138 Views 6 Replies 4 Participants Last post by  jeff swisher
Diagnosing a problem with a Ford 9"..It's been 8 years since installing the new POSI carrier and gears.

When turning corners it appears that the clutch pack is not gradually slipping because half way through the turn the rear end lurches, sometimes rather violently. I suspect that the clutches are worn and "sticking" but it could be something else.

I drained 4 oz. of oil and re-filled with Ford type friction modifier hoping to resolve the problem but after driving a few miles and numerous corners - no luck.

Any idears ?:(
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I'm guessing that since this is a 35 spline unit (although I've never seen a 35 spline Traction Lock) that the clutches were set up tight. You can do that in the Eaton Posi, but if you do it in the Traction Lock it will cause the clutches to bind and pop like you are describing. I've had to go back and remove some shim from the clutches some Traction Locks before after rebuilding them because of this. Changing the oil and putting in another bottle of additive will probably help a lot. Putting new clutches in it probably isn't the answer.

Also, Posi is for the Eaton clutch type unit that was installed in the Chevy rear ends. Ford's clutch type unit is a Traction Lock, not Posi.
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