For both applications on my COE 2 ton with two speed differential I used Permatex Right Stuff, without gaskets. Five years later no seeping/weeping of oil. You can look up the numbers but it will be difficult to find the gaskets.
Kent


1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix