I too was a refueling tech and service maintenance gas station giggle-low in the sixties. Most things were simpler then.

Gear oil came from a drum using a pressure gun ...

Today, with ASIAN and EURO TECH and performance/hybrid cars it is much more complicated.

In this article is a GEAR OIL CHART which gives current tech. GL-2 and -3 are now inactive -

https://www.engineersedge.com/gears/gears_lubrication_general.htm

This is the same as the great TYPE A MOBY DICK ATF debate. One cannot depend on an era publication for specs as too much has changed and what you think you are buying isn't really what the car needs or what you think it is, all of this of course IMO.

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Ted, that doesn't surprise me. When I worked at the scrubron station everything was labeled scrubron but who knows who made it? I wish I knew what the factory used in the transmissions? I use to blow a lot of the light duty 3 speeds and a few rear ends and got replacements at the junk yard, pulled the side covers off to look at the gears and they always smelled like 90W..

"Summary
Just remember that GL-4 and GL-5 are gear oil ratings, not transmission oil ratings. Transmissions
have gears and synchronizers. These seemingly conflicting requirements must be met differently.
When someone tells you that their GL-5 covers GL-4, remember they are correct as far as EP protection,
but that is only half the answer. When they say their Sulfur/Phosphorous additive will not corrode the
yellow metals, they are also correct, but if there are enough to meet GL-5 protection, they will slowly
peel away your brass synchronizers."

I rest my case. 

I think this is interesting, scroll down to the gear oil
https://www.fifthaveinternetgarage.com/overdrive_parts.php

It is innersting, as Ross Perot used to say. One glaring mistake in it; there are no brass parts in the OD itself, only the the synchros in the main box. $30 a gallon! OUCH!. You can get 2 gallons of the same stuff from Tractor Supply for about $20 with tax.

When they say their Sulfur/Phosphorous additive will not corrode the
yellow metals, they are also correct, but if there are enough to meet GL-5 protection, they will slowly
peel away your brass synchronizers."

I rest my case. 

Dobie, I realize that I am somewhat reading comprehension challenged but what is it exactly that you cipher in that text?

GL-1 is in no way comparable to GL-4. They are decades apart. That is why you only find it in equipment/agriculture supply stores.

BTW - Blocking rings will eventually wear to the point where they need replacement regardless of lubricant type.

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What about the tail shaft bushing and thats lubricated by the oil in the OD. I thought about purchasing that oil years ago but I'm to cheap to pay that price + $20 a gallon to ship.

Yeah, I forgot about the tail shaft bushing. Not strictly part of the OD but there nonetheless.

I wasn't comparing GL-4/5 to GL-1 other than for the purpose of stating that most modern gear oils DO contain sulphuryet they are labeled safe for yellow metals. The article simply validates the fact that ANY sulphur will eventually damage the synchros prematurely compared to normal wear when using GL-1.

No, the statement states that both GL-4 and GL-5 contain modern formulations and unless a manufacturer's lube chart specifically calls for GL-5, GL-5 (or 6) cannot be used for transmission fill  as the GL-5 concentration is much higher in GL-5 rather than GL-4.

GL-5 and GL-6 are meant for the DIF in most instances.

Just admit it, you are just too damn cheap to buy current TECH fluid ...

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