Thread: Posi??

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Originally Posted by Damien_63

I'm lookin for a new rear end because I'm getting kind of tired of only leaving a single burn out mark. Any suggestions as to what route to go for 383 w/TH350?

I'm surprised that the rear end is still together, I tore 3 of them up when I had the 400 in my '62.

Damien,
"posi" or pisitraction is a General Motors term for a clutch type limited slip. Other car companies use different names for the same principle. In addition to clutch type limited slips, there are also designs that do not use clutches; they use ratchets or some gear form instead. However, all get lumped into the "posi" bucket.

When you ask if a particular rear end is a posi, the answer is maybe yes and maybe no. There is no axle type that is always either a limited slip or not a limited slip......limited slip was and is an option. Therefore, just because you buy a 9-inch Ford axle, you dont know if it is or is not until you check it.

"posi" or limited slips use the same ring and pinion as does a non-posi axle...a non posi axle is referred to as an "open" rear end. The carrier is the part that the ring gear bolts to....it is different for a posi. If you have an open rear end, you can change it to a posi by replacing the carrier and setting the mesh on the ring and pinion.....or you can have it done by a compentent mechanic.

The addition of a posi does not make the rear axle stronger.

hope this helps you understand

mike in tucson