1984 3 speed transmission

[Selo]

Gentlemen,

I have a 3 on the tree 1984 C10 with the original 250 inline 6. I bought it used in 1985. This truck is as basic as it gets. The only option installed was a step bumper.
The original 3 speed was replaced with what I think is an earlier model 3 speed (long story).
The current 3 speed is in need of a rebuild, but I'd rather rebuild and install the original transmission model. I am having difficulty determining the model 3 speed that would have been installed at the factory. I can't start looking for one until I know exactly what I'm looking for.
Any help will be appreciated.

 

[Ricko1966]

Gentlemen,

I have a 3 on the tree 1984 C10 with the original 250 inline 6. I bought it used in 1985. This truck is as basic as it gets. The only option installed was a step bumper.
The original 3 speed was replaced with what I think is an earlier model 3 speed (long story).
The current 3 speed is in need of a rebuild, but I'd rather rebuild and install the original transmission model. I am having difficulty determining the model 3 speed that would have been installed at the factory. I can't start looking for one until I know exactly what I'm looking for.
Any help will be appreciated.

Should be a sticker on the glove box door that gives the RPO code for the transmission the truck was built with. Post it someone will tell you what transmission you need.

 

[Keith Seymore]

Three on the tree = Saginaw Transmission

There were a couple different ones available based on first gear ratio.

www.gm.com/content/dam/company/no_search/heritage-archive-docs/vehicle-information-kits/chevrolet-trucks/1984-Chevrolet-Truck.pdf[/URL]

Option codes were M62 or M64.

K

 

[Selo]

Gentleman, thank you for taking the time to respond with helpful info. Selo

 

[Selo]

Hello again,

I am reviving this thread a bit. I have a different issue with the 3 speed. My truck is C10 2wd with 250 6cyl and 3 on the tree. Currently is rarely driven, but plan to drive it regularly.
The transmission was replaced back around 1997 with a GM 3 speed that I think is an earlier model trans. I just changed the diff. gear oil
and was planning to replace the 3 speed trans oil. I think the trans is some version of a Saginaw. I know that is a pretty safe guess! The issue is I can find the fill plug, but for the life of me can't find a drain plug. I figure its got to have one, but I can't find it. I feel like a d___b a__. Any of you fellows have any ideas? I plan to take pics to post tomorrow.

Cheers, Selo

 

[Turbo4whl]

https://67-72chevytrucks.com/vboard/showthread.php?t=348394

Bottom bolt on the tail housing or side cover.

 

[Selo]

Thank you Turbo! Very appreciated!

 

[Selo]

Thought I'd give an update and beg for more info. The bottom right tail housing bolt was the charm. Once I knew where to look,
it seemed kind of obvious. Anyway, got her drained and refilled with synchromesh. Thanks again Turbo and others.

The trans work followed a service of the rear differential and an engine oil change. Next I'm going to replace the U-joints for safe measure.

I could not find a sticker with codes on the glove box. Only sticker there referred to Truck Camper Loading Information. I am sending pictures of the 3 speed trans. If I can't locate a trans of the type that was from factory I'll just keep this one. It obviously needs some seals. Its only problem is the synchronizer when down shifting from 3rd. Not hard to avoid that and when necessary, double clutching seems to help. I said I was going to beg for more info.....I'm including some pictures of the trans that possibly some of you fellows can help me ID it.

Cheers, Selo

 

[Selo]

Modified question....I know it is a Saginaw, but is it identifiable as an older version of the Saginaw 3 speed? Could this model have been OEM in my 1984 truck?

BTW, with new Valvoline Synchromesh oil in the trans., my synchronizer issue is gone!

Cheers, Selo

 

[Old Guy Bill]

Those truck Saginaw 3sps were very desirable way back when circle track racing. A bunch of different version/gear ratios.
If I remember correctly we’d pull the cover and count some teeth, we wanted a 1:68 second gear?

 

[bucket]

Modified question....I know it is a Saginaw, but is it identifiable as an older version of the Saginaw 3 speed? Could this model have been OEM in my 1984 truck?

BTW, with new Valvoline Synchromesh oil in the trans., my synchronizer issue is gone!

Cheers, Selo

Looks like there might be a date code? It's upside down. Too blurry for me to read though.

You must be registered for see images attach

 

[Selo]

I'm going to crawl under with a big light and look for the date code. Will report back. Thanks for the tip.
Selo

 

[Selo]

Gentlemen,
I'm back with some pictures. Got these as I was under the truck replacing U-joints. What a job! Except where the differential yoke joint caps were held by straps with C-clips.
the other three pairs were held in by plastic. For a half-ass mechanic with no torch but a little propane job, these were a real pain to get out. How's that for whining?

So, to the pictures....I am hoping the castings and stamp on the transmission will tell me more about the units age. Any help you may provide will be very appreciated.

Selo

 

[Selo]

The transmission fluid change to Synchromesh seems to have improved shifting, particularly 3rd to 2nd downshift.
I took her out for a post U-joint install test run of about 30 miles and the drive shaft didn't fall out so all good for now. Here she is
in the Foodlion parking lot. Windshield is next as well as rust converter on hood and roof.
Cheers, Selo