Hi Jack,
Power up A/P system --
test by engage in heading mode. Alt hold on.
Grab stick and force full up/ down climb/ decent -- note power required to
compare with ailerons.
Push aileron full left-- then right.
Note difference to elev force.
Pull cotter key on roll servo clutch and tighten till same as elev (or even
tighter).
What's happening is clutch is slipping.
Betcha!!
Charlie K.