https://www.summitracing.com/parts/yga-26024

Would this work with my 12 bolt O type 28 spline rear end on my 68 Cutlass Supreme? Currently have open 2.78 gearing I believe. Asked for help from a local shop but they don't like working on BOP posi rear ends they said they had issues in the past. I just got new 28 spline axles from Yukon

 

The description says it’s for an 8.2” rearend, so no it will not work in an 8.5” O-Type.

 

FYI, you don't have a "BOP" axle. You have a Type O, which was only installed in Oldsmobile cars from mid-1966 through 1970. Don't expect to find any parts for it at Summit, Jegs, or any Chevy-centric vendors like that.

 

This is the correct one for the "O" axle

https://www.summitracing.com/search/...-8-5-in-o-axle

 

Wow, I stand corrected. Thanks for finding that.

 

I also did not know these were available. Thanks for posting! This is great news for O-Type owners.

Be aware that the part number is very similar to the 8.5” corporate 10 bolt carrier (that one has -1 at the end of the part number). So if you buy one make sure you are sent the correct part.

 

You're the man. Thats what I was looking for. Thank you.

 

UUuummm, my day to be dense. The add clearly states
"GM 8.5 Oldsmobile Axle". I see no mention of O TYPE.
What am I missing?

Puzzled,
Owen

 

Summit Racing Part Number:
YGA-10301
Differential Case Design Type:
GM 8.5 in., O axle
Aftermarket Carrier Style:
Clutch-type
Cover Bolts:
10
Carrier Series:
3
Axle Shaft Spline Quantity:
28
Manufacturer of Axle:
GM

 

I was curious about that as well so I went to the Yukon Gear web site to confirm this was correct for the O-Type, and there is says for Oldsmobile 3.08-3.23 series gears. Note that Oldsmobile 8.5" is the O-Type.


https://www.yukongear.com/partslist....YDGGM8.5O-3-28

 

I wonder how the Yukon clutch posi holds up under abuse, as in the drag strip? The only product of Yukon's I have used were their 26 spline 7.5" open spider gears. After breaking the pins off a no slip then destroying a ring and pinion after factory soft spider gears exploded on the street, I put in their spider gears. They looked perfect after multiple runs on slicks. Hopefully for the big price, it is a strong unit.

 

All 8.5 12 bolt olds posi unit are ALL on Back order in the whole country.
Yukon was sending people tro me as I was one of the last that had these in stock as I stock my shelves MOST of the time but ran out VERY fast once word got out...
SOooo we all wait.

This is like when Richmond was bought out by Motive gear and we waited 3-4 years for the gears to be built again...
Remember this is not a high priority for Yukon as they are normally a 4 x 4 rear differential supplier.
Will see I check up on them every other week to see what is happening ...not to say I am really get good answer of course.. lol.
Finally SUMMIT is WAY over priced... I sell the same unit for much less. ...WHEN I get them in, like summit is waiting also.
Jim JD Race

 

Jim, thanks for the info. It’s nice to hear from an “insider” about this kind of thing. I appreciate all you do for us gearheads.

 

Jim - Are the Yukon unit above and the "8.8 ford units machined to 'O' type" the only new carriers that are available for the Type O rear?

 

ill add, jim will set you up with a whole kit to rebuild the rear for less than others,is available on the phone, checks the parts before they leave. i bought a set up from him,although i havent driven it yet, the markings on the gears was easy to set. ive no doubt itll be excellent. he da man