Hopefully someone can help. I have a 1991 Z28 with a blown rear, I believe all GM cars switched to 28 spline axles in 1990? mine still has the original 28 spline axles, a friend has a 10 bolt disc brake rear but im not sure what year. Does anyone know if the disc brake axles will fit in the drum housing if the posi unit isn't 28 splines? I have very little (almost no money to work with right now but need to fix it). I looked in the Hollander interchange, which lists different part numbers between disc and drum brake axles, but doesn't state wether they can be interchanged or not. Any info is greatly appreciated

 

Yes disc axles will go into a drum rear; sometimes not the other way though. Some axles have flanges with a slightly larger OD that will fit inside drums but not inside rotors. But those are mostly older ones, from back before rear discs were very common.

The correct path for you depends on several things:

1. How exactly your existing rear is "blown"
2. What gear ratio your existing rear is (specifically whether it's 2 series - 3.08 or lower; or 3 series - 3.23 or higher)
3. What gear ratio the other one is (must match the other)

Tell us those things and we can tell you whether you can mix & match.

I also note your personal info says "Eaton locker".... if this is a Gov-Lock, no doubt that's what's "blown". Those things are GARBAGE and have no business in a car on pavement with power.

 

To answer your questions, yes it's a GOV-LOCK. It's 3.42's right now but originally was 2.73 with the Auburn unit. I've installed a bunch of ring and pinions over the years in various cars so I'm good figuring out the other details. Thanks for the insight with the axles, that's the one thing I wasn't sure on. BTW, the carrier is cracked in 3 places, all of which branch away from the cross shaft, also missing 2 teeth on pinion gear.