Need help with 3 speed identification chevy vs. corvette

[Joseph T.]

What are the main case, side cover and tail #'s for a 1957 Corvette 3 spd and are they different from the Chevrolet 3 spd?

Did the Corvette use a Saginaw or Borg Warner 3 spd.

I have no experience here.

Joe

[Chris S.]

Re: Need help with 3 speed identification chevy vs. corvette

Joe
The main case is 3845122
The bell housing is 3733365
The side cover is 3731911
The tail shaft is 3737450 - it has two notches on the end of the housing

Hope all is well Joe

Chris

[Joseph T.]

Re: Need help with 3 speed identification chevy vs. corvette

Joe
The main case is 3845122
The bell housing is 3733365
The side cover is 3731911
The tail shaft is 3737450 - it has two notches on the end of the housing

Hope all is well Joe

Chris

Chris..Many Thanks!

I picked up a complete 3 spd along with shifter w/the number below. Not sure the application or the balance of numbers.

Main Case 3743368 dated F57
Tail is cast R10H-1A WG Div

Not sure of the other numbers yet..

[Chris S.]

Re: Need help with 3 speed identification chevy vs. corvette

I know the tail shaft is vette only - because of the shifter boss cast in the housing
The side case and main case I think were passenger car as well - but I could be wrong
I just built a 3 sp for my Fuel car.

I have a spare main case if you need one - it needs rebuilt
I cant remember the number on the side cover.

[Joseph T.]

Re: Need help with 3 speed identification chevy vs. corvette

check out the pictures in the auction result link and let me know what you think it is. I suspect passenger car but thought it was a pretty cool piece either way.

http://www.ebay.com/itm/141263730756?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649#ht_22wt_966

[Cecil L.]

Re: Need help with 3 speed identification chevy vs. corvette

Looks like a modified overdrive.

[Gary C.]

Re: Need help with 3 speed identification chevy vs. corvette

Joe,

The photo you've posted is very interesting. As a previous poster pointed out it resembles an overdrive unit with a floor shift. Also, the input shaft tapers after the splies. The shifter looks like a late '57 and up 3 speed shifter. The shift gate was widen for 3 speeds when the 4 speed came out in May. Why, best guess was to produce only one version of the shift gate?

Gary
....

1957 3 speed transmissions description:
- Corvette 3 speeds were Saginaw
- input shaft is same diameter after the splines all the way to the input bearing. Passenger car input shafts are reduced after the clutch splines except for heavy duty applications such as Taxis, etc.
- Corvette side covers the shift levers splines and bolt notches are opposite from passenger cars - cars levers point down, Corvettes levers point up bolt slots on bottom of shaft
3 Speed Exploded Parts Book picture.jpg

[Joseph T.]

Re: Need help with 3 speed identification chevy vs. corvette

Joe,

The photo you've posted is very interesting. As a previous poster pointed out it resembles an overdrive unit with a floor shift. Also, the input shaft tapers after the splies. The shifter looks like a late '57 and up 3 speed shifter. The shift gate was widen for 3 speeds when the 4 speed came out in May. Why, best guess was to produce only one version of the shift gate?

Gary
....

1957 3 speed transmissions description:
- Corvette 3 speeds were Saginaw
- input shaft is same diameter after the splines all the way to the input bearing. Passenger car input shafts are reduced after the clutch splines except for heavy duty applications such as Taxis, etc.
- Corvette side covers the shift levers splines and bolt notches are opposite from passenger cars - cars levers point down, Corvettes levers point up bolt slots on bottom of shaft
[ATTACH=CONFIG]52637[/ATTACH]

Thanks Gary & Cecil..I will study it in more detail once it arrives. The Nassau car has a three speed in it so I will check this one against it.

Joe

[Gary C.]

Re: Need help with 3 speed identification chevy vs. corvette

Joe,

1957 Corvette 3 speed transmissions are fully synchronized. IIRC the passenger cars 3 speed transmissions are not.

Upload a photo of the tail shaft with the shifter remover. It will be interesting to see if bubba welded on floor shifter mount or ? From what I can zoom in on the listing you posted, the floor shifter adapater mount is goes between the rear mount bracket and the transmission.

It's definitely an add on floor shifter to a 3 speed overdrive transmission. Interesting that a Corvette floor shift was used.

Here's link to ebay listing on a 3 speed overdrive transmission.

http://www.ebay.com/itm/1954-66-Chevy-3-speed-completely-rebuilt-transmission-with-overdrive-/271431358769?pt=Vintage_Car_Truck_Parts_Accessories&hash=item3f3291d931&vxp=mtr

Gary
....

[John N.]

Re: Need help with 3 speed identification chevy vs. corvette

[QUOTE=Gary Chesnut (5895);705125]Joe,1957 Corvette 3 speed transmissions are fully synchronized. IIRC the passenger cars 3 speed transmissions are not.Upload a photo of the tail shaft with the shifter remover. It will be interesting to see if bubba welded on floor shifter mount or ? From what I can zoom in on the listing you posted, the floor shifter adapater mount is goes between the rear mount bracket and the transmission. Gary-What is the part number for the low gear synchronizer for the 3 speed and gear number?Regards

[Gary C.]

Re: Need help with 3 speed identification chevy vs. corvette

John,

The gear information in that chart came Stan Edmunds and Paul Henricksen years ago.

3725646 is the first/reverse gear number. Don't have a synchronizer part number.

Tom Trainer rebuilt my last 3 speed transmission almost 20 years ago. Tom couldn't find the synchronizers and had to make them.

Gary
....

[Chris S.]

Re: Need help with 3 speed identification chevy vs. corvette

check out the pictures in the auction result link and let me know what you think it is. I suspect passenger car but thought it was a pretty cool piece either way.

http://www.ebay.com/itm/141263730756...49#ht_22wt_966

I notice the spacer inbetween the tail housing and main case
also the speedo cable is in the main case vs being the in the tail shaft

[Tom P.]

Re: Need help with 3 speed identification chevy vs. corvette

The 55-65 3sp transmissions---------------for BOTH passenger cars and Corvettes were Saginaw (including the 3spOD in pass cars).
First gear WAS NOT synchronized.
The most significant difference between the pas car and Vette 3sp trannys was the tail housing, which had threaded bosses for mounting the shifter.
The Corvette and 55-57 pass car 3spds had the same length tail housing, BUT, the 55-57 pass car tail housings DID NOT have a tranny mount nor the threaded bosses for a shifter. Thus, even though a pass car tail housing is a direct bolt-on swap for the Corvette tail housing, it cannot be used because of lack of the tranny mount and shifter mounting.
The 58-later pass car tail housingd DID HAVE the tranny mount, BUT, they are SHORTER tail housings and DO NOT have provision for mounting a shifter.
Bottom line, ONLY a Corvette tail housing for the 3sp will work in a Corvette.

[John H.]

Re: Need help with 3 speed identification chevy vs. corvette

1957 Corvette 3 speed transmissions are fully synchronized.

Gary -

If that's so, I've (again) learned something today - I wasn't aware that any production Saginaw 3-speed had 1st gear synchronized until the redesign in 1966.

[Ray K.]

Re: Need help with 3 speed identification chevy vs. corvette

The synchronizer unit for 2nd and 3rd gear as used for 1955 - 63 passenger cars and Corvette was # 3774720. Three speed transmissions for 1964 -65 vehicles required synchronizer # 3849090.

Ray