Any one know of the top of their head the recommended weight on the fluid for a 66 MKII standard trans with overdrive?

Thanks

 

Correction: the manual transmission uses 30 weight OIL, not fluid. (not 90 weight).

another poster from Australia said Penrite Gb30 oil

90 weight is for the differential and steering wheel box.

 

Engine oil and EP oil (Extreme Pressure) do not have comparable weight ratings. A 30W engine oil is actually equivalent to a 90EP oil in viscosity. The difference between the two comes from the extreme pressure additives that could harm some brass or copper components in your gearbox. I my 1964 Alfa Romeo gearbox, which uses brass synchro rings, I do use 30W oil for that reason, as the old 90w gear oil recommended by Alfa Romeo is no longer available.
JP
1960 3.8 l Mk2 Auto