The trans can be drained. The fluid clutch, aka torque converter, has a drain plug. Rotate the engine until it appears and remove it. The ATF will drain out.
These transmissions shift firmly so don't be alarmed.
Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor
Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL
ENTER > = (HP RPN)
Not part of the in-crowd since 1952.