Yes,...
You can actually leave the potentiometer in the servo. Sometimes you
have to leave the pot in servo, as the gears sometimes use the pot as
a hub pin. In this case, you turn on your transmitter, and center the control
that you are planning to use for the winch/servo. Then turn on the reciever and servo.
Turn the potentiometer back and forth till the servo stops. Then cement the
potentiometer so that it will no longer turn. If there is a gear that rides on the pot, then
take a small drill bit, and bore out the flat spot in the hub so that it can turn freely over the pot.
Reassemble the servo, and you should be good to go.
Another method, would be to center the pot as perviously described, then use a multi meter to
measure the resistance to each side. Typically the pots are 5k, so it should measure 2.5k...
Purchase some resistors to match, and place these between the three wires that the pot is
normally soldered to. In this fashion the motor will turn either way non stop when your transmitter
control is moved away from center.