Who Made the 3 spd and 4 spd Transmissions?

[Gregski]

The Greg dropping by here from the 3rd Gen section. Guys can you learn me something, I am trying to figure out who made the manual transmissions in the 1st Gen trucks, the wiki just says:

3-speed synchromesh manual
4-speed synchromesh manual

and gives no linky link to click on unlike for the 2-speed Powerglide automatic

can you teach me something please

[jdl71]

There were 2 3 speeds, once Muncie and one I think Saginaw. One has a longer tail shaft than the other and I believe one has a syncro'd first and the other doesn't but off the top of my head I can't tell you which is which and I have at least one of each. The 4 speed was a Muncie SM 420. Hopefully someone smarter than me will jump in here shortly.

[Palf70Step]

In addition to the 3 speeds from Muncie and Saginaw, Borg-Warner also produced a manual 3-speed used in the trucks. I believe the warner was the shorter. Only difference I remember between the muncie and saginaw is the mounting holes on the extension covers

Most of the 4 speeds were muncie or Saginaw. I cannot remember if a 4 speed was made by warner or not.

[Gregski]

Originally Posted by jdl71

There were 2 3 speeds, once Muncie and one I think Saginaw. One has a longer tail shaft than the other and I believe one has a syncro'd first and the other doesn't but off the top of my head I can't tell you which is which and I have at least one of each. The 4 speed was a Muncie SM 420. Hopefully someone smarter than me will jump in here shortly.

Very cool, thank you for providing a model number even, it helped me find this to confirm

"The SM420 is an impressive, heavy-duty truck transmission designed for and used in ½, 3/4, 1 and 2 ton trucks. The SM420 was made by General Motors from 1947 to 1967. Military specification versions were made through the early 1980s. The SM420 is found in GM trucks, busses, heavy equipment and various military applications.

The "SM" in the transmission's designation stands for Synchro-Mesh, in the tradition of other GM gearboxes, though we have heard that it may refer to Stewart - Muncie, a merged transmission division of GM."

The Novak Guide to the GM Muncie SM420 Transmission

[Gregski]

Could that 3 speed Saginaw been the Saginaw M15 model? Just having fun learning that's all don't need any parts or nothin

[1963c-10]

The stock Muncie 3 speed was the MC318 and it was not synchronized in 1-2 gear.

They did use several Borg Warner 3 speeds...... T-16 HD but that was in 1968 in GMC.
Borg Warner T-89 HD synchronized 3 speed was correct for 60-66.

Saginaw wasn't used in the 1st gens from the factory that I'm aware of.

Powerglide was the auto trans until the TH400 was optioned in late 65 or 66......

And the 4 Speed was the Muncie SM420 as listed above. The SM465 came into play in 68.

[Gregski]

Originally Posted by 1963c-10

The stock Muncie 3 speed was the MC318 and it was not synchronized in 1-2 gear.

They did use several Borg Warner 3 speeds...... T-16 HD but that was in 1968 in GMC.
Borg Warner T-89 HD synchronized 3 speed was correct for 60-66.

Saginaw wasn't used in the 1st gens from the factory that I'm aware of.

Powerglide was the auto trans until the TH400 was optioned in late 65 or 66......

And the 4 Speed was the Muncie SM420 as listed above. The SM465 came into play in 68.

Outstanding info, thank you very much! now can you update the Wiki page for us, ha ha

[1963c-10]

No problem.....there was also an overdrive 3 speed manual that could be optioned.....was basically a MC318 with the overdrive....was the MC319

[Keith Seymore]

Originally Posted by 1963c-10

Saginaw wasn't used in the 1st gens from the factory that I'm aware of.

There was a (passenger car type) Saginaw 3 speed available in first gens.

Our first new truck was a '69 GMC (straight six) with a column shifted Saginaw. We removed the 3 speed and replaced it with a floor shifted Saginaw four speed. They are the same external case and dimensions.

K

[Lugnutz65]

I can tell you that my 1965 C10 had a 3OTT and first was NOT synchronized. What a pain that was the first time I drove it. I decided right then and there that it was gonna Go - Go - Go!

[jdl71]

Originally Posted by Gregski

Outstanding info, thank you very much! now can you update the Wiki page for us, ha ha

I was wondering why you were wanting this info. Is that really what you are doing with it? If so, cool

[jdl71]

Originally Posted by Gregski

Very cool, thank you for providing a model number even, it helped me find this to confirm

"The SM420 is an impressive, heavy-duty truck transmission designed for and used in ½, 3/4, 1 and 2 ton trucks. The SM420 was made by General Motors from 1947 to 1967. Military specification versions were made through the early 1980s. The SM420 is found in GM trucks, busses, heavy equipment and various military applications.

The "SM" in the transmission's designation stands for Synchro-Mesh, in the tradition of other GM gearboxes, though we have heard that it may refer to Stewart - Muncie, a merged transmission division of GM."

The Novak Guide to the GM Muncie SM420 Transmission

"Impressive" is understating its durability, IMO. I think you could run one of these in a tank. Or run over one and it would still work. It's like an AK-47, nothing fancy or modern but you can leave it out in the woods in the rain for months, pick it up and work the action around to loosen it up and it will fire.

[Gregski]

Originally Posted by jdl71

I was wondering why you were wanting this info. Is that really what you are doing with it? If so, cool

Just learning, though I am planning on replacing my Muncie SM465 with an overdrive transmission, again I have a 1974 ride so a bit out of my element here.

[frankslagoon]

these are the three speeds used in the light trks.bottom is a Muncie . middle is a Muncie with o/d. top is a Saginaw and it also came in a o/d in 66 and up. I do have some Borg-warner 3 speeds with o/d but didn't know they used em in 60 thru 66 p.u.