What posi is this?
- Thread starter ham1974
- Start date
- Status
It is not an Eaton since there are no clutch packs....this an Eaton with an S spring but it could still have the 4 springs and be an Eaton. The Eaton has the cut outs for the tabs on the clutch packs. I would say, besides being real dirty, it's an Auburn
That appears to be a Borg Warner 7.5" locking differential also known as an Auburn.
From the GM Illustrated parts catalog: Page 5-17
Note: IF CASE, CLUTCH CONES OR SIDE GEARS ARE DAMAGED, IT S NECESSARY TO REPLACE THE CASE ASSEMBLY-GROUP 5.510.
From the GM Illustrated parts catalog: Page 5-17
Note: IF CASE, CLUTCH CONES OR SIDE GEARS ARE DAMAGED, IT S NECESSARY TO REPLACE THE CASE ASSEMBLY-GROUP 5.510.
the cover has 10 bolts though and I think all the BW were 9 bolt and 7 5/8
https://www.drivetrainspecialists.com/gm/gm-775-9-bolt-borg-warner/
the cover has 10 bolts though and I think all the BW were 9 bolt and 7 5/8
https://www.drivetrainspecialists.com/gm/gm-775-9-bolt-borg-warner/
That is a "Australian Borg Warner Rear End" that also used a Borg Warner Differential.
B&W cone style positractions were a factory option on 7.5's until about 1985. 8.5's got Eatons.
"Auburn Gear" was spun of from Borg Warner around 1988, so there was no "Auburn" differential factory installed in a G-body. It was a Borg Warner" differential.
that's interesting but I can't find any info on that. The F body forums if it's a 9 bolt they call it a BW but they refer to the 10 bolt as an Auburn. I went to the BW site and tried to look up the rear ends they put in GM cars but came up empty. The only thing they had in GM passenger cars was a small turbo. I found the BW 9 bolt were used in F bodies from 85 to 89, the 10 bolts were used 82 to 92. Do you have any links you can share. I like reading about these little know facts....
http://sethirdgen.org/reardata.htm
Sure. The Oficial 1982-1990 Buick Illustrated parts catalog:
Calling it an "Auburn" would be like calling Donald Trump "Mr. President" in 2012.
I'm sure he would have liked it, but everyone around you would think you were nuts.
Last edited:
Thanks, I turned to to save my neck...The retainer plates look flat on the ops so I don't think he has the 10 bolt WD. Do you know if these had a bolt in axle like the other BW rear and if they were stronger than the Auburn
They are held in with C clips just like Eatons or aftermarket Auburns. The only thing different is the differential itself per the illustrated parts book.
I looked up the date of the sale of Auburn Gear from Borg-Warner and I was confused. It was in 1982, so 1983-85 Borg Warners could technically be called "Auburns", but the GM literature didn't change because they still called them "Borg-Warner" as late as 1990 in the manual updates. The Cone style clutch is a Borg-Warner design/patent going way back to the mid 60's and Borg-Warner sold tons of them to MOPAR for 8 3/4's.
I don't know what a 10 bolt WD is. The Spring retainer plates in the OP picture have the same semicircular cutouts, one side case window and 2 piece case as the ones in the GM illustrated parts book, so it looks pretty Borg-Warnery.
- Status
