I look forward to seeing the photos and hearing what the problem turned out to be.
There is a wooden storage box that sits just above the floor in each of those "wings." It is nailed up so it doesn't drag on the floor when the slide moves. When I first got my 220 and extended the slide, a piece of wood (construction debris) was on the floor underneath the dinette. When the box passed over the loose piece of wood, it jimmied the box loose and it was dragging on the floor.
I don't know if this is related at all to what you're experiencing, but thought I'd mention it.
2013 Surveyor SP220
2010 Silverado LT 5.3 V8
The world is a great book, of which those who never stir from home
read only a page. - St. Augustine