I have a 08 Allegro Bus. The hydraulic slide came out of adjustment. The rear end of the slide had dropped a bit and would not close as the slide came into contact with the flooring. Frankly I don't understand why this would happen.
In any case, Tiffin suggested I make the 8000 mile round trip to repair/adjust it.
I had a good look at it and spoke with HWH as well. HWH only make the mechanism and Tiffin installs rollers. HWH could not help because they do not know what Tiffin does to support the slide.
Finally, the 'inboard' roller adjustment - there are 3, is simply a Bolt with a 3/4 head that tightens to drop the roller down. You may need to pull out a drawer or look under a couch but they are all there. On mine I added 4 complete turns and it lifted the slide to where there is around 3/8" clearance to the floor.
Interestingly, when the slide is out, it is entirely sitting on the inboard rollers, the outboard rollers have a gap to the slide. When the slide is in then both rollers are in use.