There is usally a top cover that is designed to be removed. This is the manual override. You may have a small crank handle that does not seem to fit anything. This is what it is for. The cover is over the top of the screw that the motor turns. A little white grease in here is all it needs, if you are not experiencing trouble I would let this sleeping dog lie. The scews may be rusted in place or you may have trouble re-sealing the cover after opening it.
WBCCI #5501 AIR # 49
1978 Argosy 28 foot Motorhome
Wise men talk because they have something to say; fools, because they have to say something. -- Plato