Technical Non-Posi GM 12-Bolt Upgrade ... question

I've got a 40 Ford Coupe with a non-posi GM 12 Bolt rear.
I want to upgrade it to a posi without replacing the whole thing.
Any ideas?

Thanx.

 

Yes get a 12 bolt posi unit and put it in. Of course you have to set up the R&P but you should not have to reset the pinion just keep the shims in the order you took them out, put new bearings on the posi and new bolts in your ring gear.

Pat

 

If your gear ratio is OK, you just need to change the carrier. I used an Auburn in mine, but the factory style Eaton is available and a couple more brands I can't think of right now. The Auburn was one of the least expensive when I was shopping. Check Moser Engineerings website, they have several different types.

 

Check this out. http://www.summitracing.com/parts/pwt-1910-lr/overview/.

 

Thanks to all your inputs and help on this.
Great stuff guys.

 

If you can't set up rears this is probably your best option

 

not all 12 bolts are the same. There are chevy's then buick/pontiac's. I really can't remember all the facts but I think that the buick/pontiac ones don't have c-clips and have a smaller ring gear. like 8.5 where a chevy has a larger ring gear like 8.8

 

Buick Olds and Pontiac have a 12 bolt cover with a 10 bolt ring gear, and non c clip axles Chevy has 12 bolt ring gear with c clip axles.

 

Just make sure you get one that will work with your gear ratio if you are not changing gears.

 

Powertrax unit, install it in an afternoon, instant Detroit locker posi!!

 

Max gearhead beat me to it, dammit!!!

 

powertrax units work great and no need to reset things