Q. Does 1946 2 ton 4 speed have PTO "Power take-off" ?
A. Yes
Q. Would lift bed, cause the transmission to need more transmission gear oil to fill it up?
A. No
1946 Chevrolet truck transmission Specifications page On bottom of page, left column, it says "Power take-off"
Look to the right, 4th column, which is the 2 ton, 4 speed tranny, Power take off left side.
Bottom row says 5 1/2 pints lubrication capacity.
Lift bed hydraulics has its own separate fluid system.
What series number is your 2 ton truck?