American Refining Group (formerly the Kendall Refinery) has gear oil for vintage transmissions and gears.
Made from 100 percent Pennsylvania crude oil, Brad Penn Penn Grade 1 “Classic” GL-4 SAE 80W-90 Gear Oil is especially formulated for use with “yellow” metallurgy – brass, bronze copper and other “soft” metals used in synchronizers, bushings, thrust washers and other transmission components. ARG claims that where GL-4 is specified, a GL-5 lube with higher extreme pressure additive concentrations can damage soft metal components. $4.95/quart.
