Trans ID Help?

[chevytrucksonly]

If you can help me confirm this tranny it would be helpful. The truck I think it came out of is a 90 3500, I ran the VIN and came up with this;
MM4 TRANSMISSION,MANUAL 4-SPEED(MERCHANDISING OPTION) 4-SPD MANUAL TRANS PROVISIONS(MM4)
M20 TRANSMISSION,MANUAL 4-SPEED(MUNCIE) 4-SPD M/TRANS(M20)
The #s on the casing are NF 9 GM 465462 9264 there is no plate.
Below are some pics if you can help me verify it. If not do you have any thoughts about what it may be.
If it is a Muncie are they a good trans?

Thanks Michael

 

[bk95td]

SM465 Was used from at least the 70s to early 90's. Very tough tranny but no overdrive. I had a 78 3/4 ton with one and have a 91 3/4 ton with one.

 

[RI Chevy Silveradoman]

Muncie transmissions are very good.

 

[iamdave0887]

Looks like a SM465 Muncie to me. Have one in my K-5 after i did my conversion. Just be careful they don't look it due to it's small size, but they are heavy. ~175 lbs. Talk about "shit your spine" heavy if your not expecting it.

Here's some really good info on them.

http://www.novak-adapt.com/knowledge/sm465.htm

to take some info from that link.

They are practically bullet proof, and are a coveted trans by offroaders due to the low("L") gear of 6.55.

L - 6.55
1 - 3.58
2 - 1.57
3 - 1.0 (direct)

No overdrive. The overdrive trans back then was the NP833, but they are very hard to find, and almost impossible to get parts for. They weren't nearly as strong either.

I will say this. Make sure whatever your putting it in has decent rear end gearing. my K-5 has 3.08s and the shifts of a SM465 are very wide due to the gear ratios. in 1st i can wind it to 2,500, shift to 2nd and be just over 1,000. Makes getting up to speed sort of painful, but thankfully the truck is light compared to a 3500. I'd make sure you've got at least 3.42s. Either that or a gasser that revs higher than the 6.2 in my K-5 does.

 

[GM Guy]

I have 3.42s in my 91, and wish I had faster gears, like 3.23 or 3.08, as it screams at road speed, and it is plenty slow in 1st, so it could stand faster gears....or an NV4500!

doesnt the SM stand for Saginaw Muncie?

 

[chevytrucksonly]

Thanks All for the data and help.
Michael

 

[iamdave0887]

I have 3.42s in my 91, and wish I had faster gears, like 3.23 or 3.08, as it screams at road speed, and it is plenty slow in 1st, so it could stand faster gears....or an NV4500!

doesnt the SM stand for Saginaw Muncie?

SM stands for Synchro-Mesh.

You can have my 3.08s any day. I'd settle for 3.42s and 33" tires. right now, with no overdrive, the engine runs ~2,000 rpm at 60 mph. Not bad, right in the power band, which i don't mind. BUt it's getting there that's almost painful. I can't even wind the engine up enough to build anything over 5 lbs of boost from the Banks turbo.