1962 Rear axle Identification, ratio tag?

[David B.]

Re: 1962 Rear axle Identification, ratio tag?

Thanks, very close to your print with more detail showing the cuts. I notice there is no 2 hole 3.55 tag shown and the print was drawn 12-5-58 which COULD indicate they were not on 55-56-57 & 58 cars. I think my prints might be correct for those years but will research further and not take up any more thread space.

[Gary C.]

Re: 1962 Rear axle Identification, ratio tag?

There was no 3:55 ratios used in the 1957 Corvette - that's when the cut tags were first used. IIRC 3:55 didn't reappear again until 1959

[Joe M.]

Re: 1962 Rear axle Identification, ratio tag?

I have a copy, I believe is from an old corvette news, that gives specs etc on the 57 and the base engine and powerglide is indicated to have come with a 3:55.Noland's book doesn't mention what gear ratio came with a powerglide. ???

[Dan A.]

Re: 1962 Rear axle Identification, ratio tag?

The Corvette section of the '57 Chevrolet Finger Tip Facts book lists the gear reductions for the Standard 3.70:1 differential and the Optional 4.11:1. It goes on to say that the 3.55:1 ratio is used with the Powerglide transmission.

[David B.]

Re: 1962 Rear axle Identification, ratio tag?

I do not think there is any question about the gear ratios offered in '57. However, there were 1,736 powerglide 1956 corvettes less (1 RPO 471B) that called for being equipped with the 3.55 ratio. All of these would have had the round tag marked 3.55. While this ratio was not offered on the 57 powerglide Corvette it would now be marked 3.36 since the same round tag was carried forward into 57. A close look at Roy,s 3767632 print which I found in Volume 5 number 3 (I was member #11) shows item no.1 part no. 3741069 as having a gear ratio of 9:32 which computes to 3:55. This is the ratio shown on the round tag in this print but differs from the 3:36 shown in the 3767632 chart attached. I could not read the small numbers in the attached print so I cannot determine if there is a discrepancy. If Axle ID Tag Chart 3767632 is what is being used to determine it's tag configurations for mid year 57 I would have a problem with that one. As previously mentioned it appears this tag chart was not drawn until 12-5-58 putting it around the time '59 production started. Further, it appears this part number 3767632 was not utilized until far after 57 production. I am sure the 56-57 Tech Manual Committee has some solid documentation to justify tags utilized in 57. As for 3767632 either version, I am satisfied it explains rear axle tag configurations at least starting from 1959.

[David B.]

Re: 1962 Rear axle Identification, ratio tag?

I have to stand corrected on the previous comment I made with regards the 57 powerglide equipped corvettes. Old NCRS spec guides (which I was looking at) list 3:36 as the gear ratio for all 57 powerglide Corvettes. This is not correct (hopefully new NCRS editions have corrected). The 57 powerglide Corvette came equipped with the 3:55 gear ratio which was the same as '56. The round tag attached to this rear axle continued to be marked "AE" which is correct for the 3:55 ratio.
The 3:36 gear ratio was adopted in '57 primarily for the powerglide and turboglide passenger cars as a result of the introduction of the 14-inch wheel which required a lower gear reduction. Since the Corvette still maintained the 15" wheel it was not necessary to change. However, it was offered as an option in particular for the 3 speed close ratio transmission equipped Corvettes with the 3:70 ratio.
Since this thread was originally a question re: the 62 tag I apologize for getting off the subject. Any further comments in this regard should probably be directed to the new forum on tech corrections etc.