4 speed transmission oil choice?

hi, a good quality synthetic gear oil will work the best. it will lubricate in the cold as well when it's hot. 140 and 90 do not lube when it's cold, the trans will run dry till the oil gets hot. this is the leading cause of trans wear.
I've used synthetic geat oil in my trans for years. there's no wear.
mobil or conaco, are two very good quality gear oils.