I have a 3.27 ratio 87/88 Borg-Warner Axle and cannot get parts for it so, I'm gonna put the regular axle back in, but my question is, can I put the Posi-diff and the axles into the regular 10-bolt housing, or do I have to just get different gears to get the 3.27? The rear axle is worthless to me if I can't even get so much as break pads..... so I'll do a build on a 10-bolt housing instead. Thanks.

Joe

 

No. They are not interchangeable. You can get parts for the 9-bolt they are just harder to find and more expensive than equivalent 10-bolt parts.

 

The 10 bolt gears will be 3.23, not 3.27. No parts are interchangable between the 10 and 9 bolt.

 

Drat... Ok, I'll have to look around & see what to do, where can I find parts for it? Thanks for the reply

Joe

 

what parts are you needing? I assume you have aluminum calipers? I bought an extra rear end off CL for $100, just sitting until I need the parts...

 

There are many threads on this. Run some searches and you'll find more than you'll ever need to know.

 

I got the calipers but need ebrake cables pads, cover gasket, I wanna rebuild the differential & replace the bearings. I just have the axle, rotors & calipers. My calipers face opposite sides.

Joe

 

Though i'm concidering a 10 bolt housing n building it up.

Joe

 

Autozone has bearings and the cover gasket. Randy's ring & pinion has good complete rebuild kits. You will probably need to re use your ring.gear bolts though, I had absolutely no luck finding those. Motive makes a 3.70 gear set. A guy on this forum (I believe it's James C) sells caliper brackets for the 1le aluminum calipers as well as posi shims.
That should get you started.

 

BTW, Ratech ring gear bolts listed for the 9 bolt (aka GM 7.75") are NOT correct. Also their pinion nut is garbage.
Thanks to Big Gear Head for all his help on my project!

 

They're good axles, but if you think you'll have a 9 inch or a 12bolt at any point in the future you may want to hold off. They're good, but the money they cost to rebuild isnt worth it unless your posi cones are in good shape, and even then you need to evaluate whether or not you need a 9 inch at some point. Dont use posi additive in them.

Andwhat's wrong with ratech's ring gear bolts? They're in my car as we speak. I like everything I've ever gotten from them and I've never had any issues. Are you sure you didnt get the wrong bolts from them? my 9-bolt is filled with ratech parts and I havent had any problems out of it. I used their solid pinion spacer too, so I didnt have to torque down the pinion nut to a million ft lbs to crush the crush sleeve so that may have something to do with me not having an issue with their pinion nut.

I have a Yukon gear 3.70 in it, so there's at least one other option beyond Motive. I bought that gearset from BigGearHead years ago, and I've got no complaints with that transaction either.

I've got no problem recommending ratech, everything listed for the "7.750 (9-bolt)" is applicable. Or it fit mine at least.
http://ratechmfg.com/gmstandard.htm

 

I was going from big gear head's observation when I was patterning my ring gear. He noticed that the bolts Ratech sent me were actually Chrysler ring gear bolts. The part number was correct but apparently the bolts they sell have a 5/8" head with no flare underneath the head. The problem seems to be the surface contact with the ring gear. I looked at both side by side and there is less than half of the contact area with the bolts Ratech sent me. He also cited a post on nastyz28.com where the guy had these very bolts back out and trash his housing! As for the pinion nut , I have nuts from both Ratech and Randy's and the Ratech nut has just a few 3/16" or so dimples to lock it down, while the Randy's nut is fully stamped.
All other parts I got from Ratech seem to be just fine.
I mentioned Motive gears because that's what I have, I know there are others and Yukon is first rate.

 

I've had more than one rear end lose the ring gear bolts because the head was too small. The Ratech bolts don't hold up well with most GM rear ends. Ratech is not the only company that uses these bolts, so I recommend checking before buying a kit. The 9 bolt has a different bolt with a smaller head, but a larger contact area under the head. This will keep them from making an impression in the differential case and coming loose. A 10 bolt should always have ring gear bolts with the 3/4 inch head.

 

Thats interesting to know. I'll go ahead and change the fluid in mine again and see how they look. Thanks for the heads up.