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Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Most Cutlass Supreme's in 72 came with the 2.56:1 rear axle, but since you have a 455, the standard axle was the SA 2.73:1 same as my car. You may have one of the other two listed in this chart though.
I'm going to guess at your next question.
IF the axles were 3:08 or 3.23, what would the letter codes be? They would be SC and SR respectively.
AND, since your car was built 06B the ordinal date will likely be somewhere in the range of 165-169
Most Cutlass Supreme's in 72 came with the 2.56:1 rear axle, but since you have a 455, the standard axle was the SA 2.73:1 same as my car. You may have one of the other two listed in this chart though.
I'm going to guess at your next question.
IF the axles were 3:08 or 3.23, what would the letter codes be? They would be SC and SR respectively.
AND, since your car was built 06B the ordinal date will likely be somewhere in the range of 165-169
Is the date code facing towards the front or rear of the car? And btw, axle housing isn't rusty but will have to sand it...somebody gave it a good coat of paint at some point in the years past....oh, and it's a posi....
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Should be facing the rear of the car. Posi (limited slip) rear axle is RPO G80 and could be ordered with any gear set. If your car was originally used to pull a light trailer chances are you have 3.08:1 gear set.
It has a stamped code on the right side of the axle tube just around the vent tube area. It will have a 2 letter code and an ordinal date. Ex: My car came as a stock 72 Cutlass S which has 2.73:1 gears. That's code SA on the axle tube. My car came off the Lansing assembly line on April 10, 1972. The axle is stamped with the ordinal date of 0101, which is April 10 (since 1972 is a leap year and my car was built after Feb, add 1 to the 100 that is set against the 10th, making it spot on for the production date.
I have a picture of it somewhere in my picture files, hang on and I'll look for it. Here it is. Luckily I only used 220 grit on the sander but you can make out the code and numbering. See the vent on the top of the axle? The axle code will be down on the rearward facing part like this. Hopefully your axle isn't too badly rusted.
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Hey Allan I'm confused about where to look for the date code. Here is a pic of my rear axle right side. Could you please point out where the code would be? Thanks.
Hey Allan I'm confused about where to look for the date code. Here is a pic of my rear axle right side. Could you please point out where the code would be? Thanks.
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Have a look at my picture again and relate it to this one I high lighted for you. BTW, something just doesn't look right with your differential cover. Can you post a picture of all of it?
Have a look at my picture again and relate it to this one I high lighted for you. BTW, something just doesn't look right with your differential cover. Can you post a picture of all of it?
I found the code and what it looks like is SD 8 1022...and here's the pic of the whole axle
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Code SD with anti spin axle is gear ratio 3.08:1
SD B 102 2
Interesting. Your axle was produced 1 day after mine, but at a completely different plant. Mine was Lansing - yours is Freemont. I suspect the extra stampings are from the shifts that produced them.
SD B 102 2
Interesting. Your axle was produced 1 day after mine, but at a completely different plant. Mine was Lansing - yours is Freemont. I suspect the extra stampings are from the shifts that produced them.
So the million dollar question..numbers matching drivetrain?
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Unfortunately there's no way to prove the axle, unless you have the build sheet, there aren't any VIN derivatives on differentials like there are with engines.. Likely it's original though.
Have you looked to see what code is on your TH400? Should be OD
SD B 102 2
Interesting. Your axle was produced 1 day after mine, but at a completely different plant. Mine was Lansing - yours is Freemont. I suspect the extra stampings are from the shifts that produced them.
Just checked the gear ratio...three and almost a half turns of the driveshaft to 1 turn of the tire...with the bigger tires would it be safe to assume it's in fact a 3.08?
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Depends on how you indexed the tire and prop shaft. It's not that accurate to turn the wheel 1 time and get the approximate right ratio. You need to turn it 10 times to see if the prop shaft turns almost 31 times, a little over 32 etc. That's a far more accurate way to do this. You did have both rear wheels off the ground to do this right? It helps if you have someone help you with this - one person counts wheel rev and one counts driveshaft revs
The tire size shouldn't matter if you use the wheel as your index. What size wheels do you have anyway?
Depends on how you indexed the tire and prop shaft. It's not that accurate to turn the wheel 1 time and get the approximate right ratio. You need to turn it 10 times to see if the prop shaft turns almost 31 times, a little over 32 etc. That's a far more accurate way to do this. You did have both rear wheels off the ground to do this right? It helps if you have someone help you with this - one person counts wheel rev and one counts driveshaft revs
The tire size shouldn't matter if you use the wheel as your index. What size wheels do you have anyway?
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Perfect. Do the related counts and you'll get the accurate gear ratio. If it's OEM axle in the car you'll get around 31 revs of the driveshaft for 10 turns of the wheel.
Perfect. Do the related counts and you'll get the accurate gear ratio. If it's OEM axle in the car you'll get around 31 revs of the driveshaft for 10 turns of the wheel.
My best calculation is just over 33 turns of the driveshaft to 10 turns of the wheel...the guy I bought the car from said it had 3.80...giving myself a margin of error and the possibility the guy transposed his numbers (3.08 instead of 3.80) I think I'm running 3.08..agreed? Also, is this what I'm looking for on the transmission?
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
I'd agree. The 15" wheel will likely make up that difference since the original wheel on the car was 14"
Yes, that is your Transmission tag. Proper with OD and looks like it's never been off.
I'd agree. The 15" wheel will likely make up that difference since the original wheel on the car was 14"
Yes, that is your Transmission tag. Proper with OD and looks like it's never been off.
So engine and tranny verified...now is my drivetrain numbers matching?
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
It would appear to be. Like I said earlier the guaranteed proof is the build sheet. If you ever drop the gas tank and find it on top, you'll find all the codes that show your cars born with components.
It would appear to be. Like I said earlier the guaranteed proof is the build sheet. If you ever drop the gas tank and find it on top, you'll find all the codes that show your cars born with components.
That is my next objective...once my tank is empty of course😀. What concerns me is that the previous owner had the tank cleaned and re-lined, so hopefully it will still be there...
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
That's a long shot then. They would have had to take the tank out to clean and reline it. You might also want to have a look under the parcel tray. I've heard of some being found there.That's just as much work as taking the tank out though and no guarantees either.
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
Yes, that's the space between the seat upright and the rear window trim. It's called a parcel tray in the GM Parts book. It's my pleasure to help you. There will likely be other things you have questions about and you might consider starting new threads to ask those questions. That will get you the largest exposure to the crowd on this site. Some have way more knowledge than I do, others will offer their opinions of what they think you should do with your car. That's just the way it is with on line forums. If someone is really being a bada$$ you can report it to the administrators by clicking on that red/white triangle below your post count. It will give you the opportunity to point out the problem to the moderators or an administrator. The CO population and threads are very well policed IMO so you should be golden on almost everything.
The reason I suggested the parcel tray BTW, is one of our beloved and deceased members found her build sheet there and if memory serves, her car was either Freemont or Framingham. Can't remember which.
Thanks for the advice Allan, and not being a stranger to on line forums I know things can get pretty dicey at times. But it's good to know we have big brother on our side😀
If I look for the biuld sheet under the package tray, wouldn't I see it from inside the trunk, or is there more to it than that?
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
It's possible. Sandy saw hers partly revealed in one of the rear speaker hole cutouts. She never did take it out though. It all depends on IF its there or how it was tossed by a production line worker.It's not all that common to find them there though.
July 28th, 2018, 05:37 PM
