1967 3OTT transmissions?

[Warrens69GMC]

What transmissions came behind the inline sixes with the 3OTT in 1967 C10's?

[jocko]

67 CS10 3OTTs:
Standard: Chevrolet synchromesh (2.94, 1.68, 1.00 and 3.14 reverse - only 2nd and 3rd were synchronized).
Optional: Chevrolet fully synchronized (2.85 1st and 2.95 reverse) - this trans was standard for CE10.
Optional: Chevrolet fully synchronized trans mentioned above - with overdrive.
Hope that helps

[Warrens69GMC]

Well I was trying to see if it was a Saginaw or a M20, etc.....

Was looking to see what the torque rating on these transmissions are.

I'm looking at a 1967, longbed Six cylinder/ 3ott, and getting up to speed on this year-only items.

[68 C10 Driver]

It is a Saginaw, mine was similarlyequipped. I replaced that transmission with a M20, which is a 4 speed. The truck was converted to a floor shift back when my father-in-law owned it, so to me the M20 made sense...and it is period correct for the truck.

Here is a pic of my M20, I have since changed out the rods for the correct ones for the truck and eliminated the plate aluminumshifter mount and mounted the shifter on the tailcone like it should be:

[jocko]

Originally Posted by Warrens69GMC

Well I was trying to see if it was a Saginaw or a M20, etc.....

Was looking to see what the torque rating on these transmissions are.

I'm looking at a 1967, longbed Six cylinder/ 3ott, and getting up to speed on this year-only items.

Sorry Warren, I was trying to answer the question asked in the first post.

For a 68 I6 3OTT truck, there were only three possibilities - all posted above.
Have you seen the SPID yet?

• If no "M##" RPO is listed, it came with the standard Syncromesh 3OTT.
• If RPO M17 is listed, it came with the optional Fully Synchronized 3OTT (which was also standard on a CE10). This RPO could only appear on a CS10.
• If RPO M10 is listed, it came with the optional 3OTT w/overdrive.

I "think" all the 3-speeds available in that year were Saginaw, but don't quote me on that... Don't know the torque ratings. Do the torque ratings matter? It's a 3OTT... none of them were made for racing but they're all stout enough for a 68 CS10. The real difference between the 3 3OTT possibilities isn't necessarily their torque ratings - rather it's just different variations of synchronization & 1st and Reverse gear ratios - and whether there is an overdrive gear.

A 3OTT truck would not have an M20 RPO listed as that is a truck 4-speed option - generally the SM465 in 1968. Not to be confused with a car 4-speed of the same era, different animal.

[Warrens69GMC]

I haven't even seen the truck yet. The seller says it's a 292 with a 3OTT. I was doing homework to see how it was equipped.

[Keith Seymore]

Originally Posted by jocko

Sorry Warren, I was trying to answer the question asked in the first post.

For a 68 I6 3OTT truck, there were only three possibilities - all posted above.
Have you seen the SPID yet?

• If no "M##" RPO is listed, it came with the standard Syncromesh 3OTT.
• If RPO M17 is listed, it came with the optional Fully Synchronized 3OTT (which was also standard on a CE10). This RPO could only appear on a CS10.
• If RPO M10 is listed, it came with the optional 3OTT w/overdrive.

I "think" all the 3-speeds available in that year were Saginaw, but don't quote me on that... Don't know the torque ratings. Do the torque ratings matter? It's a 3OTT... none of them were made for racing but they're all stout enough for a 68 CS10. The real difference between the 3 3OTT possibilities isn't necessarily their torque ratings - rather it's just different variations of synchronization & 1st and Reverse gear ratios - and whether there is an overdrive gear.

A 3OTT truck would not have an M20 RPO listed as that is a truck 4-speed option - generally the SM465 in 1968. Not to be confused with a car 4-speed of the same era, different animal.

Excellent response and totally correct.

K

[special-K]

It gets confusing with GM using M20 for completely different transmissions.

[Keith Seymore]

Originally Posted by special-K

It gets confusing with GM using M20 for completely different transmissions.

Couple things:

a) Yes - RPO codes do get reused during different eras of production

b) Also - the RPO code is not intended to indicate a specific brand or supplier. Even if the code is consistent (ie, "manual trans - non overdrive", or "Rear Axle - 3.42 ratio") it doesn't mean it's tied to a manufacturer like Dana, or New Process, or Saginaw or American Axle or whatever. Only the enthusiasts try to do that.

K

[Warrens69GMC]

HERE'S the gem. I suppose I could have done worse.

[Warrens69GMC]

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[Warrens69GMC]

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