1957 corvette 3 sp transmission?

[Kevin P.]

Can anybody tell me if the 1957 pass. 3 speed trans is the same as 1957 corvette 3 speed what should i look for as in numbers or mounting. Thanks kevin

[Joe L.]

Re: 1957 corvette 3 sp transmission?

Can anybody tell me if the 1957 pass. 3 speed trans is the same as 1957 corvette 3 speed what should i look for as in numbers or mounting. Thanks kevin

Kevin-----


The 1957 passenger 3 speed manual transmission is different than the 1957 Corvette. Among other things, the extension housing and side cover are different.

[Kevin P.]

Re: 1957 corvette 3 sp transmission?

Thanks joe

[Gary C.]

Re: 1957 corvette 3 sp transmission?

Kevin,

Do you want all the casting numbers ?

Gary
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[Kevin P.]

Re: 1957 corvette 3 sp transmission?

Thank you gary, but i think i am all set. Kevin

[Gary C.]

Re: 1957 corvette 3 sp transmission?

Kevin,

The gear set is close ratio. There were some passenger car close ratio 3 speed transmissions. Difference in the cases as Joe pointed out.

Big difference on the v/8 3 speed is the input shaft, it's same diameter all the way. Where as the 6 cylinder input shaft is tapered along the shaft.

Have all the gear numbers, teeth counts etc if you need them.

Gary
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[Jim L.]

Re: 1957 corvette 3 sp transmission?

Big difference on the v/8 3 speed is the input shaft, it's same diameter all the way. Where as the 6 cylinder input shaft is tapered along the shaft.

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Gary, just to be clear, are you indicating that in '57 all 3 speed gear boxes for V8 applications had the thick input shaft or only the close ratio gear boxes?

Reason I'm asking for clarification..... I own a '57 V8 3speed wide ratio box which has the necked down input shaft. Also among '57 model year gear boxes I've never seen one with the thick shaft. However, I've never knowingly seen a '57 close ratio box. The only gear boxes I've seen with the thick shaft were from later production, altho I don't know how much later.

Jim

[Gary C.]

Re: 1957 corvette 3 sp transmission?

Jim,

I've had 3 1957 Corvette 3 speed transmissions with Jan to March assembly dates and all had the thick stem 29 tooth input shaft. IIRC the one 1956 3 speed I had the input shaft had a vent hole in it.

The '58 P&A 30 3 speed transmission illustrations shows the thin shaft as 6 cylinder. All the '57 passenger car 3 speeds I've had were thin stem.

Probably should've said Corvette 3 speed instead of V/8 - sorry my CRS kicked in.

Gary
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[Chris S.]

Re: 1957 corvette 3 sp transmission?

I do please
I need a 3 sp for my 57 Fuelie

[Dan P.]

Re: 1957 corvette 3 sp transmission?

The main case and side cover cast numbers are the same . The difference in the side cover are the shafts . Because the shift arms on A Corvette point up and the passenger cars point down. The cast number on the tail is different because the rear motor mount and the shifter on the Corvette bolt to the tail housing. Not so on a passenger car . A lot of the gears were changes in these cars because some people did not like the close ratio gears, or they were blown up and replacement gears installed. .

[Gary C.]

Re: 1957 corvette 3 sp transmission?

Chris, attached PDF with gears and cast numbers. Gary....

[Chris S.]

Re: 1957 corvette 3 sp transmission?

Thank you Gary
Now - to find one.....

[Steven B.]

Re: 1957 corvette 3 sp transmission?

Chris, attached PDF with gears and cast numbers. Gary....

Thanks Gary! Much appreciated. Steve

[Terry B.]

Re: 1957 corvette 3 sp transmission?

Kevin, here is some additional information that may help you with your transmission question. Many years ago, about 1987, "The Corvette Restorer" had a two part detailed article covering the CR 3 speed transmission used between 1955 and 1962. It was written by Paul Henricksen and I think Stan Edmunds. The first article was titled "1955-1962 Corvette Three-Speed Transmissions" and it covered the side cover and tailhousing. It discussed casting numbers, part numbers and the years used with pictures. The next issue (I think) had part two entitled "1955-1962 Corvette Three Speed Transmission Spelled Performance". This issue covered gears, bearing retainers and case. It also had part numbers, casting numbers and photos to help show what was being reviewed. In total this is a very detailed and clearly written article and would be well worth your time in tracking it down. If you can dig up these two articles you might pay attention to what is said about the input shaft. It would seem there were two different input shafts with three different variations. As I understand it the thick stem was used in the beginning run of this transmission while the thin stem was used there after. Hope this helps. Good luck.

[Gary C.]

Re: 1957 corvette 3 sp transmission?

Jim Lockwood,

I found a 29th tooth thin stem input shaft with drilled through oil hole in my pile. Not sure what transmission it came out of.

Over the years the 3 speed parts I have were sorted through by lots of NCRS guys building 3 speed transmissions.

Gary
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