Valvoline makes a manual trans lube in qt. squeeze bottles, Synchromesh MTF, I use it in my SM420 and have zero trouble with it. The rear differential needs a different lube, something for hypoid gears, 80W-140 or 75w-90. I think the tranny is around 9 pints? rear end on yours might be about the same amount.
Last edited by 78buckshot; 11/08/2023 9:14 PM.
