Gehl 4500 Chaincase Oil

[snowman0650]

I just bought a '79 Gehl 4500 and am changing some fluids (as well as head gasket). I drained the chaincase oil and got about 5 gallons out on one side, it was milky so I am not sure how much water was in it. The manual says it takes 1 gallon of 10w40 on each side, is that right? Just guessing, that seems pretty low, that may get to the chain/sprocket but not a lot higher. Just looking to verify.
Thanks,

HL 4300-4500-4600-4700 Manual: