As I dimly recall, the "drive" gear goes around the forward yoke on the 4-speed's u-joint?

http://chevy.oldcarmanualproject.com/parts/1929_54/220a.htm

If that is the case, follow the instruction in the Shop Manual for transmission/u-joint removal. And, be sure to follow the instructions for gasket adjustment when replacing the u-joint bell/ball cover (universal joint ball adjustment).

The forward yoke for the 4-speed u-joint is held in place with a bolt (and heavy washer) through the middle of the yoke.