Can anyone help me de-code the numbers of my rear axle: 3A72 GM ZG 337
Help will be greatly appreciated. Car is a 69 442.
Thanks
Jerry

 

Sorry for the mis-information. The numbers in above post are from the differential, not the axle.
Jerry

 

Jerry,
There should be a two letter stamp on the passenger axle tube, generally between 2" and 5" outboard of the differential case. Some say the stamping is on front-facing surface, others say the rear-facing surface. You may find them on the top or bottom, as well. The letters will be about 3/8" tall. For instance, my '68 442 came originally with "SE" coded rear end. This represents an open carrier with 3.23 gear set. The same gear ratio in an anti-spin carrier would be coded SF. There are charts posted here in CO that document the codes and what gear sets and carrier (open/anti-spin) they represent.

Sometimes the letter codes can be (very) hard to find/see. I have yet to find mine stamped on the tube, but I have since opened up the rear to swap out the open carrier to anti-spin.

 

Thanks for your reply.
Later today, I intend on lifting the car and I will attempt to find the numbers/letters you mentioned. The numbers Originally posted are from a photo the previous owner has taken when he had the differential open. Was hoping someone could identify these numbers.

 

Pics below show what the axle code looks like on a couple of my rearends. They can be very difficult to see due to rust, dirt, etc.

As for those numbers, most folks ID the carriers by the large numbers cast into the sides of them (671, 672, 673, 588, etc).

1970O-Type12boltcodelocation.jpg
196812bolt342HDopendiffTLcode.jpg

 

I found the following number/letter stamped into my pax side axle
Appears to be upside down 7S. 7 is completely upside down. If I can figure out how, I'll post a pic of it. Stamp is on back side of pax side axle approx 5-6 inches outboard of center section.

 

Is it likely that whoever stamped this they used a upside down 7 as a L. Making the code LS?

 

If the code is S7, that means you have a 3.23:1 anti-spin differential with power brakes and your front brakes are disc. Do you have disc brakes?


Randy C.

 

Thanks for the info. Yes I have power front disc brakes. Your response is very helpful. May I ask where you came up with your info. I have not been able to find info on S7 in any combination.
Thanks again
Jerry

 

I have a pamphlet from Supercars Unlimited in Beaverton, OR (www.supercarsunlimited.com) called "4-4-2 By The Numbers". It has a lot of good info in it and has come in real handy on many occasions. I do believe those codes are in the Product Information Manual (i.e., Assembly Manual) for the 1969 4-4-2/Cutlass as well. And I'm sure there are other publications out there with this info that I'm not aware of that others may identify.


Randy C.

 

I archived some differential info from the Olds e-mail list and various internet sources. Below is what I have readily accessible:




From 1970 factory Assembly Manual. This manual is generally very reliable.

Ratio Axle code

Open:
2.56 R2
2.78 SA
3.08 SC
3.23 SE
3.42 not avail.
3.91 not avail.

Limited Slip:
2.56 R3
2.78 SB
3.08 SD
3.23 SF exc. W-27
3.42 SH exc. W-27,30,31
3.91 SJ exc. W-27,30,31
3.42 TM W-30,31
3.91 TO W-30,31

W-27 Lim Slip:
3.23 SV
3.42 SX
3.91 SZ

Dealer Installed:
4.33, 4.66, 5.00



From 1982 Oldsmobile Parts Illustrated Manual, listing for 1968.
You sometimes have to take the Parts Manuals with a grain of salt; I've found plenty of errors before.

Ratio Axle code

Open:
2.56 R2
2.78 SA and TA
3.08 SC
3.23 SE
3.42 TL
3.91 TN

Limited Slip:
2.56 R3
2.78 SB
3.08 SD
3.23 SF
3.42 SH and TM
3.91 SJ and TO
4.33 TW

 

I took this straight out of my 1970 service manual.

1970%20axle%20codes_zpsn78mdyw9.jpg

 

Thanks Randy, I appreciate the info. I have ordered the FSM just haven't relieved it yet.
Now if someone can give me directions on how move pics from my album on this site to make them appear in my post, I will add pics.
Jerry

 

I can only tell you how I do it. When I write a thread or respond to one, I scroll down below what I am writing to "manage attachments" and click on it. When I do that, I get a field on the screen with options to "browse". When I click on browse, it takes me to the "My Pictures" file in my computer, where I keep all of my pics. I click on the pic I want to post and then click on "open" and it puts that pic address on the "browse" screen. If I want to add another pic, I just go to the next "browse" line and do the same thing. When I'm done, I click "upload" on the browse screen and it loads my pics into the "additional options" box below the thread. When all the pic addresses appear in the "attach files" section of the "additional options" box, I close the "browse" window. The pics in the "attach files" section will actually will post those pics onto the thread when I finish and click on "submit reply".


I'm sure there are other ways to do it...I'm fairly computer illiterate...but that's the only way I figured out how to do it!

Randy C.

 

The 1st 2 are pics of my 1st 442 in 1969. Others are the current 442. Last pic is of the code I found on my axle
IMG_0665.JPG

IMG_0666.JPG

IMG_0678.JPG

IMG_0679.JPG

IMG_0675.JPG

IMG_0673.JPG
This car scores 983/1000 at the North Texas Oldsmobile Club of America show in April 20016

IMG_0677.JPG
Hoping this works, and thanks Randy C. I used your method to load these

 

Yes, that's an S7 code. It's upside down as they usually are. Glad my method worked for you!

Randy

 

Thanks all for the help and advice. I can see that this site will be very helpful in the future. I also use the Camaro. net site frequently for advice and help with my 67 Camaro Convertible. My user name there is Hot67. If anyone has interest in seeing that car, I'll post pics later. As I'm new here and I dont know how members here a feel about other models of autos.
Jerry