Hi Guys,

I have been searching for info on a 12 bolt rear I have, and stumbled across this site.
The axle measures about 54-55 inches from backing plate to backing plate, and I think that's the right width for a Cutlass.

I believe it's an olds type "O" with a 4.33 posi, from what I have found on the net TY is the code for that gear. I have taken the cover off, an it has a 9 tooth pinion and found that's correct for that gear.I have cleaned the front passenger side axle tube and can not find any codes, but on the back side of that tube TY is stamped up side down.

The only other number's I can find are on the center section and looks like a date code of 8-5-70...the 70 is very hard to read so I could be wrong about that.

So far I have found that this rear was available for 68-69, not sure about 70.Could it be that it was an over the counter part at the dealer, and that's why the code is not where it should be?

Any one have any thoughts on what it might be out of, or if it would be worth any thing?I realise a 4.33 is a lot more gear than most people are looking for.

Sorry for the kind of long winded post,any thoughts or info on this would be kindly appreciated.


Thanks, Tom

 

Hi Tom
I believe your on the right track, it sounds like it's a 1968 or 1969. The reference book I'm looking at says that the date is only the month and day stamped in it, just to the right or left of the inspection cover. It could be that a previous owner swapped the rear or even the internals. If you decide to sell it please post your city and state as shipping would be a killer. If you were close to my location I would be interested in either the complete rear end or just the internals. John

 

The code is in the correct spot of a 12 bolt olds. They only have a 2 letter code ...all the rears I have that are 12 bolt olds are all like this... I have not really check into the specifics on these rears ... It take a hard core olds guy to stay with these rears because they are rare and parts are expensive and hard to find anymore.

I am certain there is a buyer for this rear. We just need to find them. Some Nastalgic drag racer guy I am sure would love it. You know all the stock class drag classes out there are a big deal now.

I have a 3.90 all Original 12 bolt olds I am working on right now. this one is TO code.

Where are you? If your in Ohio I would be interested in looking at it and checking some things on it. Always learnign and studing different set-ups esspecially if they are untouched originals. Jim

 

Thanks Guys,

I got it out of the shed today so I could look at it a bit closer, and it does only have a two letter date code. As near as I can tell (and I'm no expert) I don't think its ever had more than the cover removed, everything looks as if it's as it came from the factory. All the bolts look to match each other, and it has GM on the ring and pinion.

2blu442, I'm in Michigan...so, yeah kinda not very close to where you are.
I would really like to know what cars might have came with this rear.

I took a bunch of pic's and uploaded them to photobucket, If any one would like to check em out.

http://s187.photobucket.com/albums/x...lds%20Rearend/

Thanks for the help so far, Tom

 

I have a 1969 W30 that's missing the correct engine, trannie and rear But talking to a previous owner from 25 years ago it used to have a 3.91 posi rear end. A reference book I have shows the 4.33 as being a factory option in 1968 and 1969, then it says that the 4.33, 4.66 and 5.00 could have been dealer installed options. I wonder if the two letter code would be there if it were a dealer installed ratio? I would expect it to have come on a 442, W30 or possibly a special order car. Beyond the ratio code and date there's probably nothing else we can tell about it's history. Yeah, I'd love to have it, but it would need to be shipped by freight on a pallet. Any idea what kind of price you would want for it? Or is there anything your looking for that you'd accept in trade? Send me a pm if you'd like to discuss it. John

 

Well I can tell you someone has messed with the rear. The bearing cap on the passenger side is on upside down.

I would have to say this 4.33 would have come on some up scale olds 442 I am sure long since dead in a junk yard. I am also sure someone would need it for a restoration out there some where. Just ahve to fine him/her.

Good luck with it. Jim

 

Or a "plain Jane" F-85.

Norm

 

Anything is possible back then. You can order anything as long as you paid for it...lol. Know a days you get packages and really do not get to build your car. Jim