I have a 1966 Ford Mustang 200 Cyl with a 4 speed manual Dagenham transmission

I need to change the oil in the transmission and would like to know what kind of gear it needs, any help is greatly appreciated.

75W-90W gear oil.
This is the consensus.
Do not overfill the box.

Hi so as dagenham is here in the UK how on earth did a mustang get it fitted as it would not be strong enough on a V6 or V8 engine. The drain plug is on the bottom and the oil filler and level plug is on one side half way up the side of the gearbox.

Any auto parts store can look up the factory recommended gear lube for you to buy. You might want to ask them how much it takes too!

200 cylinder engine?