What were the stock manual trans options for these trucks?

[kipps]

I'm aware of the sm465 and the np833 transmissions. The sm465 was the classic granny-low four speed, and the np833 was a four-speed with overdrive specifically for the lighter weight trucks with the 6.2 diesel.

What were the model numbers of the three-on-the-tree transmissions? What years were they offered, etc?

Are there any other manual transmissions that came stock in these 73-87(91) trucks of one-ton and smaller?

[D13]

Two different 3 speed manuals were offered, both column shifted (3 on the tree). My 1981 3/4 ton has the HD one, and the 1977 1/2 ton had the light one, both 250 six cylinder powered.
If you go to the heritage site you can pick thru the optioning packages to see the codes and availability.

A833 was also available behind 4.3 and 305.

[Keith Seymore]

M62 and M64 were the non merchandised option codes for the three-on-the-tree, selected based on low gear ratio driven by other power train considerations.

MM3 was the merchandised RPO.

And - the NP A833 was available with small gas engines too ( not just diesel).

K

[kipps]

Correct me on this info where I'm wrong. I'll go back and edit the post so no one gets bad info from it.

1. The MM3 rpo code designated a truck with a three-on-the-tree transmission.

2. This MM3 rpo code could have either of two Muncie transmissions; a m62 or a m64.

3. (was one of these the "heavy-duty" version that poster "d13" mentioned?)

4. Both of these transmissions were side loaders, and were only available on the 2wd trucks.

5. The four-speed np440/np833 was available behind the diesels and the smaller gas engines as a fuel economy option. This transmission didn't have the deep unsynchronized first gear that the sm465 was known for. It did have an overdrive gear.

6. The np440/np833 could have had an iron or an aluminum case on the 2wd trucks. The 4wd trucks were iron only.

7. The bolt pattern was partially different between the np440/np833 and the sm465. Some, but not all, 1980's bellhousings were cast and drilled to fit both patterns.

8. Did the m62/m64 transmissions share a bellhousing pattern with the four-speed transmissions?

[Keith Seymore]

I think you are pretty close, except the M62 and M64 transmissions were Saginaws, and were available in light duty passenger car applications too (with their own various first gear ratios).


K