The Stovebolt Site Forums The Shop Area General Truck Talk 1950 GMC Manual transmission fluid

This is what I found in the shop manual……

Transmission…… 6 pints of SAE 90. No mention of what type. I’ve read/heard mineral oil??

Differential……. 4 1/2 pints of SAE 90 “Multi purpose” gear lubricant.

I read Richard Widman’s paper on GL-4 vs GL-5 oils and haven’t seen in the manual where it mentions either for use in the tranny. Only saw SAE 90. (Screenshots below)

Please point me in the right direction.

Thanks