8.5" rear axle

[rixtrix1]

Scored a 30 spline 8.5" out of a Buick Estate wagon with a 3.42 posi from Pick 'n Pull for $25. Gear ratio matches what I have already in my S10. Needs narrowed so I just made a jig. Is the 30 spline diff only found in fullsize vehicles, as I'd like to look for another one with clutches? I think mine is a cone type. Seem to be a fair amount of G-bodies there. Kicking myself for passing up the one in a late model Roadmaster a few months ago. Is there anything dimensionally different in this rear as opposed to others? I know the S10 8.5's have necked down axle tubes.


Ric

[GetMore]

I'm no expert, but I didn't think they used the 30 spline in cars. I know it was installed in trucks, and is actually 8.6", though it will fit in an 8.5" rear.
Eaton does make a clutch diff for this.

[big gear head]

All 8.5 rear ends went to 30 spline axles in '90. The truck rear ends use the Governor Lock differential, which you don't want. All of the car rear ends from '90 and up use the Auburn, which is the cone type. You r only option for a clutch type with 30 splines is the new Eaton Posi. I can get you a new one for $430 plus shipping. You will need bearings and shims to install it and set the backlash. These are $45.

As for the housing, the big car rear end will have larger brakes and it has a speed sensor on the pinion gear. These later rear ends use the same small axle bearings as the other cars. The older big cars used the truck axle bearings.

[Samckitt]

Heck of a price, $25. Wow!

[rixtrix1]

which is kind of confusing, as it's got big bearings and brakes, no speed sensor, but the car also had a 3" exhaust and Flowmaster 2 chamber on it, so things could have been changed from the original. Are all the G-body posi's 28 spline? Thanks for the help.

Ric

[big gear head]

All G body 8.5 rear ends had 28 spline axles, as well as F bodys.