jdana24

Can anyone confirm what the D7 and the 130 mean that are stamped on the side? I’m assuming the 28 is for the splines. Also, why is there a Canada 1987 stamped in the second photo? Is that when the patent ended?

monzaz

No Auburn has date usually for warranty to know when the carrier was produced. Are there any other number at all on the unit?
Usuall the last three digits are the last three in the part number of the unit.

THERE IS NO SECOND PHOTO. please get more pictures for us to see.

130

I came up with nothing on that 130 so ??? I do not know.

How many spline are in the side gears? how big are the bearing hubs. looks like it has a tone ring notch...could be ford 8.8 unit ??

jdana24

I added the additional photos. I didn't see any other numbers other than what is in these photos. I counted 28 splines. Not sure how big are the bearing hubs. This what was on the car when I purchased it back in 2007 so not sure of the history of the carrier. The prior owner said it had 3.08 gears in it.

monzaz

So it was in the rear end? Or ON IT? what ever that means...? Or do you mean it came with the car in a box inside the car thrown in the deal?

monzaz

Ok here is what I see...The holes in the carrier are oblong drilled and you can see the bolt head scrap marks are not center around the ring gear bolt holes. SO either this is a 8.8 Ford posi used in a GM or this is a 8.5 some used in a 8.8 ford rear... lol. That is what I come up with.

monzaz

If the outer carrier hub bearing is 1.78 ish inch in diameter it is a Ford 8.8 carrier

If the carrier bearing Hub is 1.625 ish then it is a 8.5 carrier.

Hope this helps.

jdana24

Just to clarify, this was the carrier in the rear end of the car (not in a box) when I purchased it. I'll check the diameter of the bearing hub.

scottv442

I believe thats an 8.2 posi 10-bolt for 3.08 and numerical higher gears.

the auburn symbol is on the carrier

ford 8.8's are shorter in the body

jdana24

A few more pictures with measurements if this helps. And anyone else have an idea on the stamped numbers? Thanks.

scottv442

US4612825 patent number for auburn case....simple google search

jdana24

Thanks Scott, but I was referring to the D7, 28, and the 130. I figured the 1987 is when the patent ended.

jdana24

Scott and Monzaz, I've attached a photo of my rear end, along with photos from Randy's Ring and Pinion. From the photos, it looks like my rear end is similar to the GM 8.5" Rear for Oldsmobile 442 & Cutlass, 28 spline. Would you agree, or is there something else that comes into play on this? Thanks in advance for your input.

Fun71

The first picture is an O-Type rear: 12 bolt cover, 8.5" 10 bolt ring gear. It is unique and very different from the later corporate 8.5" 10 bolt rear used from 1971 up to the 90s.

As monzaz said above, there are Ford 8.8 carriers that are machined to fit the O-Type rear, so that may be what you have.

scottv442

agree with Fun71.

If thats a picture of your car's rear diff. then its a Type-O Oldsmobile 12-bolt.

The Type-O uses a 12-bolt cover over unique 8.5" 10-bolt ring gear with 28 splines.

The corporate GM 8.5" ring gears and parts used in 1971 and newer cutlass/442 have nothing in common with your differential case.

Odd thing again is the Auburn posi carrier in your pictures. Auburn doesn't make a posi for the Olds Type-O carrier.

The Ford 8.8 diff machined for these 12 bolt Type-O's has the ring gear bolt locations redrilled to match the GM ring gear. Yours doesn't have the extra ring gear holes added.

my conclusion from all the info so far, is that a previous owner had the 12-bolt Type-O re-machined to accept a GM corporate 8.5" posi carrier with the Type-O ring gear and pinion.

as too the stamped numbers....don't know. probably date code and factory lot #'s

Cheers

monzaz

Really prefer you measure with a slide caliper to be more precise... 1.625 or 1.78 which it does not appear to be the later BIG hub so
Here is what the deal is. 10 bolt 8.5 and they wallowed out the ring gear bolt holes to fit the 12 bolt olds...BUT the ring gear center will not work with out the custom center ring for the carrier to ID of the ring...WITH out this ring the 12 bolt olds ring and pinion WILL FAIL! MAJOR catastrophe FAILURE!

It possibly could be a 10 bolt 8.2 but the holes would have needed to be drilled from 3/8 to 7/16 and then wallowed out after that. ALL depends on the ring gear flange height.

(picture)

monzaz

Trouble is we can not ID the case from the stampings WHICH you should be able to??? It is weird.

Get me the ring gear land measurement and will see what series they were trying to make. It will be from 1.25" to 2.25" any where in between.

Got to measure with a better instrument than a ruler... Jim

monzaz

So what did you come up with?
Patent only tells you it is a AUBURN casting nothing more. Sorry....

olds 307 and 403

I don't see any obvious cutting where the ring gear sits, it may be the 8.2" posi as said. Why did this come out in the first place?

monzaz

Get me the ring gear land measurement and will see what series they were trying to make. It will be from 1.25" to 2.25" any where in between. (picture for reference of what we need)

It appear from the carrier HUB size (with a ruler ) it is a 10 bolt 8.5 or 8.2 28 spline unit that we know.

The hub carrier bearing size is not big enough for the 8.8 ford which is 1.781" ish so that unit is OUT.

Got to measure with a better instrument than a ruler...

Jim
JD

monzaz

look between the purple and the green that is where the centering ring goes. If you look at the picture at the top of this thread you will see the shadow in the picture of where the 12 bolt Olds 8.5 ring gear was mounted and the ring gears ID (green) was NOT touching the posi body machined centering ledge OD (purple)
The red circle indicate how someone drilled /wallowed out the ring gear hole to accommodate the 12 bolt Olds 8.5 larger diameter ring gear bolt pattern.

THIS set-up was destine for disaster and the reason it is NOT in the car...IT WILL NEVER work with out a centering custom ring (we have the rings machined and then they slip to press fit of the lower body base (purple ) diameter to increase the that base diameter to the Olds ring gear inner diameter. We only tack weld the rings in place as not to weaken the case of the unit by welding the entire circumference.

If you use the ZOOM feature you will see.