Help with 4 speed transmission

[Kutzy]

Hello, everyone!
I am in need of some help identifying the transmission in my truck.
The truck is a 1980 GMC C1500 and it has either the 305/350 V8 and a 4-speed manual transmission.

According to Wikipedia, it is either the Saginaw SM465 or a New Process overdrive transmission, as these are the only 4-speeds that came in this year/model truck.

If it helps, the shift knob has an H pattern for 1-2-3-4 such as:
1-3
2-4-R

And from what I can find, the SM465 has a L-1-2-3 pattern, unless the knob was changed.

Are there any specific features I can look for on the transmission that will help me identify the model?

I appreciate any help that the educated members of this forum can provide.

[SS Delux]

If the transmission has shift linkages on the side it is a NP A833 overdrive (yup almost the same as what was in the mopars from the 70s) I have the same on but behind a 4.3L V6

[Kutzy]

Much appreciated for the quick reply!

I just looked up a few resources for that particular transmission and it is definitely NOT that model, no shift linkages.

So that must mean I have the SM465.
Is this considered a good transmission?

From what I could find on the web, it takes regular 80w90 gear oil, does anyone have any pictures/diagrams of how to drain and fill it properly?

Thanks for the input.

[big10ratrod77]

sm465 is an awsome trasmission. its realy realy heavy duty its made for towing. my 77 has 214000 miles on the orginal sm465 they dont give alot of trouble.

[dammitmitchell]

Originally Posted by big10ratrod77

sm465 is an awsome trasmission. its realy realy heavy duty its made for towing. my 77 has 214000 miles on the orginal sm465 they dont give alot of trouble.

my sm465 was in a 420hp/420 tq 4x4 that i beat the hell outta ....
it never failed me, they are slow on the shift, and the handle is ling as all get out..

but it will not fail you.

my tranny also was never rebuilt wince 83...

be warned.. they are really really realllllllllyyyyyyyyyyyy heavy.. dont drop one without assistance.

[dammitmitchell]

an 80 is most likely an sm 465. post a picture and we'll tell you in half a heartbeat.
http://www.google.com/imgres?q=sm465...:0&tx=41&ty=74

[Tucson38]

Originally Posted by dammitmitchell

an 80 is most likely an sm 465. post a picture and we'll tell you in half a heartbeat.
http://www.google.com/imgres?q=sm465...:0&tx=41&ty=74

Wow, what an informative link. Appreciate it. I've got an '85 with the original SM465 in my truck. Real rugged trans but man, sure some big gaps between gears. It would be nice to have an extra gear in there somewhere.

[Your41Plague12]

Great transmissions. They're just about as bulletproof as a stock transmission can get. Like big10ratrod77 said, they were made to tow things and take lots of abuse while doing it.

[dammitmitchell]

http://pirate4x4.com/tech/billavista/sm465/index.html

sloppy shifter repair.
it made an insane difference with mine.. we also heated the entire ball and heat treated it.. went two years of 4 wheeling and daily driving and the shifter never got sloppy again.

[Kutzy]

Thanks for all of the great feedback everyone! I definitely feel a lot better about my recent purchase. It's great to find such an awesome online resource for these trucks!

Kutzy

[RUSHNBOBO]

You may have this trans ......originally manufactured by Chrysler, found it's way into some GM pickups late seventies early eighties, originally designed as a car tranmission non OD, later to truck applications only (.74 OD 4th gear), built thru '86, check pic or rpo code "MY6"

New Process A833 4 Speed (RWD) Manual Transmission RPO Code MY6

[Kutzy]

Originally Posted by RUSHNBOBO

You may have this trans ......originally manufactured by Chrysler, found it's way into some GM pickups late seventies early eighties, originally designed as a car tranmission non OD, later to truck applications only (.74 OD 4th gear), built thru '86, check pic or rpo code "MY6"

New Process A833 4 Speed (RWD) Manual Transmission RPO Code MY6

I looked into that one as well and it's not that because mine doesn't have the shift linkages on the side.

Although the overdrive of that one would be nice

[RUSHNBOBO]

It has to be a Sm465 and someone replaced the knob, there were no other 4 speed manual transmissions in that year.... simple to identify .....a very square looking mass of cast iron, heavily ribbed, no tail housing, and bolt on yolk.

The shifting pattern for the 465 is in the standard "H" pattern with reverse gear being to the right side, and down.

[Kutzy]

Yep, I just went and looked underneath the truck and it looks identical to that photo.

Can you tell me which of the plugs are the drain/fill plugs from that photo?

[Redcap]

Originally Posted by Kutzy

Yep, I just went and looked underneath the truck and it looks identical to that photo.

Can you tell me which of the plugs are the drain/fill plugs from that photo?

Fill plug is halfway up the side of the case, should have a square head for a ratchet or extension to fit in.

[dammitmitchell]

if you would read the links i posted it will tell you everything you need to know..

[RUSHNBOBO]

Originally Posted by dammitmitchell

if you would read the links i posted it will tell you everything you need to know..

question already asked and answered

[C10NEWGUY]

anyone have any part numbers for the mounts for this sm465?