What Gear Oil

J

jeepguy1948

Well-known member
I know that lots of folks have their own opinions but I’m curious what y’all are using for gear oil. 90 wt and GL4 (that’s the hard part). Even after deciding what then you have to find it to buy it (supply chain blah, blah, blah).
 
The O'riellys (?). near me always has 140wt GL4 on the shelf, and sometimes even 90wt, but usually I have them order it. Thats for the trans, I use anything in the diff
 
I always use Sta-Lube 140wt. GL4 in trans. & rear axle. I get it from NAPA.
JD CornHead grease works good in the steering box to keep that from leaking.
 
GL4 140 is available here but has to be ordered generally takes 2 days. Has anyone got any information on GL6 spec and its suitability with yellow metals
 
I use Aeroshell SAE-50/100 grade motor oil but without the Plus (TCP additive). SAE-50 motor oil is the same viscosity as SAE-90 gear lube. It is packaged as Aeroshell 100 or W100.
The 100 is straight mineral grade and the W100 is ashless dispersant additive which has detergent qualities to hold crud in suspension. I generally just use the mineral based oil but either will work in a transmission.

Use anything you want in the rear axle. There are no soft metals in there unless you have a old Model T.
 
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I’ve ran the “600wt” form any of the early parts suppliers with good luck but often wondered if any heavy gear lube would be the same? Much easier to run to Napa then order it.
 
"Use anything you want in the rear axle. There are no soft metals in there unless you have a old Model T."

Or a Columbia!! Columbia's have yellow metal components, which may be compromised using GL5 additives?
 
CRC Sta-Lube API/GL-4 Multi-Purpose Gear Oil 85W90, Sta-Lube, 1 Gallon, Hypoid Gear Oil, Yellow Metal Safe, Anti-Rust and Anti-Wear Ep Additives
Not to hijack but I changed out the GL-5 and used this in the Muncie in the Camaro. Huge difference (better) in the way it shifts. As soon as it warms up I'm going to do the T-10 in the '49. I believe the T-10 is the big brother to the 49-43 flathead trans, basically a bolt in.
 
I think the additives in the Gl-5 do not play well with the old synchros shift quality. Just my opinion.
 
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