Im sure the slide can be adjusted. Slideslickers
work great to protect carpet , just remove the spiked nibs if your going to use them on a lino floor.
Where are the black strips you mention located?
There is a black wearbar that some slide-outs ride on. And slide wear strips on the edge of some slide outs.
If your unit is new it should be covered under warranty.
Pics are always helpful.
Oh, and welcome to the forum