slide adjustmen

Gotta 2005 Trail Cruiser 27 QBS with a Liftco, Inc. 74" slide. When closed the upper part of the frame is out about 3/4" and can feel that the rubber gasket does not contact the trailer side. Its also higher one side. The slide works fine but I need to get it adjusted so it closes tight all the way around. Anyone know how to adjust Liftco slides?