Heavy Duty Kenmore 90 Series washer Model 110.20922990 ?

The washer is in very good shape and operates through all the washing cycles, but when in spin cycle makes a scraping noise like sandpaper between the drum and tub. It will slowly get up to speed and then begin a very slow process of decresing speed.
Could the drum have slipped down lower and be scraping the bottom of the tub or some such thing. When I closely looked at the space between the bottom of the agitator and the drum, it seems to be a larger gap between them.
Before I start tearing into the machinery part of the washer from the back and bottom I would like to have an idea of what others think the problem might be.
One other point is that the drum was stuck and I pushed on two sides of the drum when the timer reached spin as the motor was running. The drum broke loose and begain to spin but with the scrapping noise. I am relitively good with electrical or mecanical problems but always like having an Idea from someone knowledgeable about the equipment I am going to attemt to repair.
I appreaciate any assitance or guidance anyone me have to suggest.
Thank You,
David