3-Speed question

[Corts60]

I got a question concerning the early 3-speed transmissions and their bolt patterns.

The bell housing on my '60 has provisions for 5 bolt holes but the tranny (SM-318) only has 4 bolts. Now, I've seen 3-speeds with five bolt holes.

The question is what trucks did the 5 bolt pattern tranny's come in and what trucks did the 4 bolt pattern come in?

I'll try and find some pics....

[Corts60]

here is my tranny with the 4 bolt hole pattern like most that I have seen

And I take that back, I don't have the 5 bolt bellhousing:

[Corts60]

Anyone? Bueller?

[markeb01]

I'm assuming you mean the mounting holes. Does the 5 hole transmission have 5 mounting ears? I'm curious where the 5th holes is located.

Most 3 speeds I've seen look like the one you pictured, except perhaps with a shorter or longer tailshaft. The only exception was pre-55 trans with a torque tube which had a smaller and narrower pattern. Do you know for sure if the 5 hole transmissions were a GM product?

[Corts60]

Originally Posted by markeb01

I'm assuming you mean the mounting holes. Does the 5 hole transmission have 5 mounting ears? I'm curious where the 5th holes is located.

Most 3 speeds I've seen look like the one you pictured, except perhaps with a shorter or longer tailshaft. The only exception was pre-55 trans with a torque tube which had a smaller and narrower pattern. Do you know for sure if the 5 hole transmissions were a GM product?

No I'm not sure it was GM.....but yes it has 5 mounting ears, sorry if I wasn't specific earlier. I'm still trying to find the picture.

[Corts60]

Here's the pictures:



Maybe these came in the big trucks?

[markeb01]

Wow that looks like the biggest 3 speed ever. The gearset must be huge. The side cover looks twice as big as anything I've seen. I think you're probably right about it coming from a big truck. It seems older with what appears to be a 10 spline pilot shaft. Of course when's the last time anybody made a 3 speed manual.

I'm curious now and going to do some more research. If you figure out what this is please post the results.

[markeb01]

Looks like it is a heavy duty GM Saginaw transmission per the following weblink:

http://columbus.craigslist.org/bar/1384236089.html

[Corts60]

Well, that's awesome! Thanks Mark.

Now I wonder what bellhousing goes with it?

[protrash64]

Originally Posted by Corts60

Well, that's awesome! Thanks Mark.

Now I wonder what bellhousing goes with it?

Do you think it would fit on your bellhousing and just skip the upper bolt?

[Corts60]

Originally Posted by protrash64

Do you think it would fit on your bellhousing and just skip the upper bolt?

It would probably bolt up, but I think they have that extra ear for the weight since there is no tranny mount on my year of truck. So it has to be an early style tranny when engines still had "rear engine" mounts instead of tranny mounts.

[MikeN]

I use a heavy duty, all-synchro Muncie 3-speed in my 64 C10. It is just as large/heavy as the transmission in lower photograph, and it works just fine with that type of bellhousing and no rear mount. I have never seen a transmission with that 5th mounting hole up top though.

[markeb01]

Come to think of it, my 1960 GMC had the granny 4 speed installed when I bought it, and it only had the standard 4 ear bolt pattern with no tail mount. It seemed that thing weighed as much as a small car engine, so I would imagine it would be okay to ignore the upper bolt on the heavy duty 3 speed.

It would be interesting to come up with a 5 hole bellhousing however, just to confirm one can be found.