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The UnMuncie Transmission
Posted by: caroseiii ()
Date: February 01, 2018 08:43PM

I was sent an errant message on eBay today complaining about my advertising a 64-65 four speed as a Saginaw transmission. In an effort to end this hearsay that early transmissions are built by Muncie, not Saginaw, I am attaching some evidence that the transmissions were all built by Saginaw Gear. The Parts & Accessories Catalog shows that all the early 3 and 4 speed are Saginaw. Read Bob Helt's book Corvair Secrets if you don't believe the Chevrolet Parts and Accessories Catalog. I understand that people like to have a shorthand to describe the transmissions but four bolt and six bolt would probably be better.

Crawford Rose

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Re: The UnMuncie Transmission
Posted by: MattNall ()
Date: February 01, 2018 08:52PM

nice info for those times....gg





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Re: The UnMuncie Transmission
Posted by: Tom Z ()
Date: February 02, 2018 05:18AM

Craig should be tired of hearing this by now- he did a tech article for the CORSA communique about the "4-speed" used in Corvairs...some never learn..

Tom Z,,Rochester NY

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Re: The UnMuncie Transmission
Posted by: caroseiii ()
Date: February 02, 2018 06:21AM

That's right, Craig Nicol has done superb work on the provenance of the four speed. If only one would read about it! I should ask him to put it in the Wikipedia entry for Corvairs, entitled "Saginaw division transmission development".

Crawford Rose

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Re: The UnMuncie Transmission
Posted by: vairchet ()
Date: February 02, 2018 10:17AM

Perhaps this could be of interest:

Chet in Ramona

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Re: The UnMuncie Transmission
Posted by: Chilly Willy ()
Date: February 02, 2018 10:24AM

eBay likely received a message from some bored person that thinks they are description police.
We’ve seen a few here😆




The Corvair, Keeping Nader Notorious winking smiley


Will
Northern California

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Re: The UnMuncie Transmission
Posted by: vairchet ()
Date: February 02, 2018 10:35AM

Additional information that could be of some use:

Chet in Ramona

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Re: The UnMuncie Transmission
Posted by: Seth Emerson ()
Date: February 02, 2018 12:51PM

"The 66-69 Corvair 3 and 4 speed is a Saginaw-built transmission" Is there anything wrong with that description? There is another specific reason the 66-up are referred to as Saginaws. It has nothing to do with earlier transmissions.

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Re: The UnMuncie Transmission
Posted by: 66vairman ()
Date: February 02, 2018 01:59PM

Seth Emerson Wrote:
-------------------------------------------------------
> "The 66-69 Corvair 3 and 4 speed is a
> Saginaw-built transmission" Is there anything
> wrong with that description? There is another
> specific reason the 66-up are referred to as
> Saginaws. It has nothing to do with earlier
> transmissions.

It took a few years to figure out why a lot of Corvair folks refer to the 66-69 as the "Saginaw" and earlier Corvair transmissions are typically called "Corvair transmissions" even though they were also built by Saginaw.

During the early 60's GM and Borg Warner got into a "disagreement" of some sort. GM had relied on Borg Warner to supply four speeds for cars, except the Corvair. Details vary, but either or both sides decided to part ways.

The time line is subject to argument, but with the big Muncie four speed taking over for the big block GM automotive applications from the old Borg Warner unit GM needed a four speed more suitable for the smaller engines (this was the age of the four speed popularity, even with small engine cars). Saginaw got the job of building the "smaller" four speed for automotive use. It was used behind engines up to and including the Chevy 327, but was NOT considered adequate for the later 350 engines. This small "Saginaw" four speed was used successfully in the Pontiac Firebird OHC six cylinder Sprint models. In 66 the newer Saginaw design was employed in the Corvair, no doubt to save costs. The added bonus is it handles more torque and was popular with the Crown V8 conversions. Note that the Corvair Saginaw had some unique parts/bearings to make it more compact. One reason some Crown folks use the "big car" clutch gear and bearings.

This is all from memory - feel free to correct or amend.

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Re: The UnMuncie Transmission
Posted by: Seth Emerson ()
Date: February 02, 2018 03:50PM

So GM had to support the earlier big car/Corvette Borg Warner T10s, 57-63 and the new for 1964 Muncie 4-speed. Stronger than the T10 to handle more HP/Torque. It cost a bundle to build that trans and it was overkill for the smaller applications. So GM designed a 3-speed / 4-speed family of transmissions for the lower HP installs (as Vairman mentioned). By 1964, the Corvair 3-sp and 4-sp transmissions were no longer sharing parts with any other GM car. That made the 64-65 transmissions more expensive. Since, unlike the BW T10 and the Muncie, the new Saginaw design had reverse in the main housing (It is in the tailshaft housing of the T10 and Muncie), GM could add a hollow main shaft, adapt a rail shifter, and squeeze it into the Corvair. The new trans could share parts with the "Saginaw" 4-speeds in the bigger cars, but didn't share any parts with the BW T-10 or the Muncie. The Chevy parts guys called the three larger transmissions by their origins, Borg-Warner, Muncie or Saginaw. The aftermarket did the same.

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Re: The UnMuncie Transmission
Posted by: caroseiii ()
Date: February 02, 2018 04:42PM

Seth, not to be argumentative, the 1964-1965 transmission used in cars and FCs is virtually identical to the 61-63 transmission used in Corvair and Tempest. The gears were improved to conform to revised production cone angles and increased torque but the transmissions were virtually identical. They kept the design for five years to expense the tooling. Note that in 1970 they offered only two early four speed transmissions, one for 61-63 cars and 61-65 FC vehicles and another one for 64-65 cars! They could have decided to use the same transmission through 1969 since the early four speeds were still being manufactured in 1970.

Crawford

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Re: The UnMuncie Transmission
Posted by: dragvairclark ()
Date: February 03, 2018 06:21AM

The early Corvair transmissions had some gears made in Muncie, IN. They were all assembled in Saginaw, MI

Clark Hartzel, Fraser, MI
1965 Monza coupe

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Re: The UnMuncie Transmission
Posted by: UGLYTRUK ()
Date: February 03, 2018 07:53AM

Link to Craigs trans article?

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Re: The UnMuncie Transmission
Posted by: 66vairman ()
Date: February 03, 2018 08:19AM

Crawford - I'm going to guess that Saginaw ran off a bunch of transmissions and parts, to supply the parts and spares demand for 60-65 Corvairs and then shut down that line of transmissions. I doubt they were manufacturing those transmissions as late as 1970.

Based on my talks with Dan the Gear Man those 60-65 transmissions may be interchangeable they are not virtually the same.

I suspect the change to the 66-69 manual transmission design would have been logical from a manufacturing viewpoint if Corvair production had remained at 65 levels.

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Re: The UnMuncie Transmission
Posted by: Seth Emerson ()
Date: February 03, 2018 12:18PM

Crawford - My note was only to explain why the 66-69 Corvair Transmissions are called Saginaws. Because they had a design similar to the big-car 4-speed that HAD to be referred to as a Saginaw in the parts system. Since it has grown into "general usage", if you call a Corvair 4-speed a "Saginaw" people will think you are speaking of the 66-69. Unfair? You bet!

Seth Emerson

Check my new Performance Corvair Web site [www.perfvair.com]

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Re: The UnMuncie Transmission
Posted by: caroseiii ()
Date: February 03, 2018 05:39PM

Since there was never any other kind of transmission in a Corvair than a Saginaw it is absurd to call it something else than what it was. These are all Saginaw transmissions, not Muncies and were not manufactured in Muncie as shown by the documentation above. I guess some don't believe what the documentation that we posted but don't post anything contratdictory. Consider the reasonableness, Why would it make sense to have a gear plant in Muncie Indiana supply gears to a gear plant in Saginaw Michigan?

Also, in reviewing an excellent article about Muncie four speed transmissions [www.chevydiy.com] , GM Muncie was not making those four speeds until 1963. "The first Muncie has several unique features that were dropped by 1964. It had a small 6207-style front bearing and an aluminum front bearing retainer. This retainer was upgraded to cast iron by the end of the 1963 run. The 3831704 cast main case is unique because the front bore is smaller than it is on later Muncies. The first-speed gear rode directly on the mainshaft. A snap ring retained the first and second synchronizer assembly on the mainshaft. The first-speed gear had a smaller bore diameter as well as a recess in the bore to clear the synchronizer retaining snap ring. It had a thrust washer behind first gear that floated on the rear bearing inner race."

Note that few of these design features exist on the Corvair four speed transmission which of course was manufactured prior to 1963 in 1960. It always had an aluminum bearing retainer and never had a cast iron bearing retainer. The front and rear bore use the same size bearing. The first gear does not ride directly on the mainshaft but rather on a spacer. There is no recess in the bore of first gear to clear any synchronizer retaining snap ring because there is no synchronizer retaining snap ring for the 1-2 synchro. The first and second gears are retained by the bearing snap ring, not a separate snap ring but the first gear does have a thrust washer (as did the Saginaw three speed). So it appears that the 1963 Muncie four speed transmission does not share these first gear design and "rear" roller bearing design features with the 1961-1965 Corvair four speed.

Considering these manufacturing differences and the GM documentation, the 1961-1965 Corvair transmission was not built by Muncie.

Crawford

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Re: The UnMuncie Transmission
Posted by: Timothy Shortle ()
Date: February 03, 2018 05:50PM

I have always "identified" the Muncie MT by its aluminum case where as the Sags were cast iron. I am guessing the (1 year only) Corvair aluminum case MT was built in Saginaw Michigan?

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Re: The UnMuncie Transmission
Posted by: caroseiii ()
Date: February 03, 2018 06:02PM

That program for the aluminum four speed was cancelled along with the aluminum three speed in summer of 1960. Later 1960 production was all cast iron. There was a defect due to leaking countershaft causing the differential oil level to drop, burning up the ring and pinion. The cast iron cases resolved this defect.

Crawford

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Re: The UnMuncie Transmission
Posted by: vairchet ()
Date: February 05, 2018 02:05PM

More interesting information that could be of some use:

Chet in Ramona

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