1984 3 speed transmission

[Selo]

Bucket,

Thank you! The transmission was changed (long story) around 1994. I was told at the time it was an earlier year trans. The truck is an 84 so, of the two choices,
that would point to a 1975. You have good eyes. I don't doubt your appraisal, but I can't decipher those numbers stamped on the trans.
Thank you again,

Selo

 

[Selo]

Bucket,
I don't remember where that code (J 27 5) was cast, but somewhere on main case. Was not on the tail shaft housing.
Selo

 

[DoubleDingo]

The gear oil should be 90w mineral oil.

 

[Selo]

DD,

Yes Sir. I put this in the rear differential.

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STP 80W-90 Conventional​

Cheers, Selo

 

[DoubleDingo]

DD,

Yes Sir. I put this in the rear differential.

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STP 80W-90 Conventional​

Cheers, Selo

I thought we were talking about transmissions here.

Having a cd of the 1981 shop manual here at work, I see it calls for 80w gl-5 for the transmission. But you says it's an older transmission, and those use the 80w mineral oil which is gl-1.

https://www.napaonline.com/en/p/NHF65201

 

[Sad Sack]

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.

Thats a like maybe a 70's tranny.

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this link may help:

Camaro Transmission Information & Restoration

Camaro Transmission Restoration Information.

www.nastyz28.com

 

[Selo]

DD,
Thanks for your information. My apologies, I've always used the term "Gear oil" in reference to differentials and for transmissions, oil or fluid. Possibly I have installed the wrong transmission oil.
My 1985 Jeep CJ with a Borg Warner T5 trans. uses Synchromesh for manual transmissions. I understood it was recommended for the Saginaw.
Thus, I installed the Valvoline Synchromesh a GL-4 recommended for manuals with synchronizers.
Are you suggesting this will damage the Saginaw?
Selo

 

[Selo]

Sad Sack,

That pretty well nails it down. Thank you for taking the time to send it and also for the Camaro web link.
I'll be back under the truck looking for the number cast on the extension housing.

Selo

 

[Ricko1966]

Check and double check what gear oil you put I'm a manual transmission. GL5 is way more common than GL4 but GL5 does not play well with brass synchronizers long-term. 80/90 that's just on part of the equation you need to check the rating as well.