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Hello all, lots of questions this week as I sort through my 1972 Vette. As always greatly appreciate all the help this forum and its members provide.
The question of the day is my rear is marked "AW" Diff code with a build date of November 30 which I assume matches nicely with my trim tag date of December 17th.
The issue is that according to a few references I have, both in book and internet, there is no "AW" diff coded in 1972.Most other year seemed to have on except 1972.
1. Is my interpretation of the Diff code correct?
2. Is this an error in the reference manuals?
3. Could my rear end have been replaced? The car is new to me but I don't see any evidence that it has been replaced?
4. Is a "AW" coded diff a 3.08 gear ratio?
Hi Ike,
In the Differential Section of the 5th Edition of the NCRS 70-72 Technical Information Manual & Judging guide there's a note indicating that although the AW code isn't listed by Chevrolet as being used during 72 production, 72 model year cars are seen with the code.
Your's being another example?
Regards,
Alan
Yes, a pretty nice date on the differential for a mid-December car!
Thank you Alan, as always you ride to the rescue!!!! Very interesting!!!
Have I interpreted the Diff codes correctly?
I thought I would look through some Corvette ads form 1972 to look at some specs and low and behold
1972 GM ad for a Corvette listing a 3.08 Diff standard with an automatic transmission which is what I have. So I would assume a 3.08 was available even though it was not listed. I wonder why /GM overlooked it??
Great stuff!! Thanks again!! Ike
Last edited by general ike; Jan 21, 2018 at 06:05 PM.
If I can add to your question. There is a good chance that your differential has been opened, with some type of service, IMO. The gasket doesn't look factory and the small "weld" on the flange seems somewhat odd to me? Here's an example of what I'm familiar with seeing.
Thank you War Bonnet for the photo. I would assume and hope that after 45 years someone went in and did some maintenance. The weld??? Is that not the same casting "flash" mark that is in your photo next to the "2"?
Jowill is this what you are referring to? Sorry its the only photo if not and I am not by the car till the weekend.
Could someone decipher the code??? Thanks great stuff Ike
Hi Ike,
I believe there are 3 casting dates on the differential.
2 on the case itself... I'm not sure why there are 2?
1 on the differential case's cover.
Regards,
Alan
as an example, and if I read this right.. it says August 18, 1970. or it could be 1980? i think at a certain point the year became 2 digits, so this is probably 1970.
as stated, if your rear end has been opened up, then you don't know for sure what is inside it. could be different carrier and different gears that don't match the stamp code..
So at minimum the cover has been replaced. The 464910 marked diff cover seems to be a common replacement I wonder why? What, besides some kind of accident would require the cover to be replaced? I know it has an aftermarket rear leaf spring on it. Not sure of it size it might be.
This weekend I will take a look and see if I can see the other codes on the rear and report back. Thanks again!!!!! Ike
Last edited by general ike; Jan 22, 2018 at 05:48 PM.
Beautiful by the way Alan. Thanks for the response. Again after all these years I assume anything could be possible.
On a side note, Alan how do you index all your photos to find them so quickly. I have about 1200 now and I often painfully go back and forth looking for something... Thanks Ike
So at minimum the cover has been replaced. The 464910 marked diff cover seems to be a common replacement I wonder why? What, besides some kind of accident would require the cover to be replaced? I know it has an aftermarket rear leaf spring on it. Not sure of it size it might be.
This weekend I will take a look and see if I can see the other codes on the rear and report back. Thanks again!!!!! Ike
Replacing the rear spring and incorrectly torqueing it will break the stock ears, hitting a pot hole or RR tracks hard can do it too.
as an example, and if I read this right.. it says August 18, 1970. or it could be 1980? i think at a certain point the year became 2 digits, so this is probably 1970.
as stated, if your rear end has been opened up, then you don't know for sure what is inside it. could be different carrier and different gears that don't match the stamp code..
Joe that would be a 1970, an 80 was aluminum. late 69's and 70's had 3 letter stampings unlike any other year range.
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"AW" Differential Code on a 1972???
