Diff swap

Arctic

New Member
Jun 10, 2022
18
Working on my 1980 Z28 . Was wondering if I swap out the open diff with a posi unit it's a 8 and 1/2 in rear end do I need to change axles or can I use the same axles.
 

Twisted_Metal

Administrator
Staff member
Lifetime Gold Member
Feb 26, 2004
31,660
Bloomington, MN
You can use the same axles but the differential needs to have the same spline count.

You can upgrade to 30 spline axles (from 28) when you do the swap.
Check for axle wear on the ends where they ride on the bearings.

If there's any wear... get new axles.

Do it once... Do it right.
 

hd_cat

Veteran Member
Sep 6, 2013
166
Cincinnati, Ohio
You can use the same axles but the differential needs to have the same spline count.

You can upgrade to 30 spline axles (from 28) when you do the swap.
Check for axle wear on the ends where they ride on the bearings.

If there's any wear... get new axles.

Do it once... Do it right.
Agree with Twisted Metal, upgrade the posi-unit and the axles, splines must match and replacement aftermarket axles should be available from Strange and other manufacturers, and were reasonable the last time I checked. I considered doing that with the 10-Bolt in the '73, then ended up buying a Strange 12-Bolt Crate assembly
 

cvon

New Member
Feb 12, 2015
8
Detroit, MI
Working on my 1980 Z28 . Was wondering if I swap out the open diff with a posi unit it's a 8 and 1/2 in rear end do I need to change axles or can I use the same axles.
Not sure of your location but I have 2 stock limited slip units that I pulled for my build which has taken a different direction and no longer needed. Both units that I have are 28 spline, casting numbers 410408N. Please inbox me if your interested, they’re just sitting on the shelf. Hopefully someone can use them.
 




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