You have seen this thread
covers the bolt problem, slide problems, broken brackets, slide stop rods you name it, its all there.
In QT's 1 & 2
all slide information is located.
Maybe this search
will help you also.
has many slide
replacement motors one of our sponsors.
I had a 2003 coach and large slide only needed a small adjustment on control pot to get slide up ramp so not as much stress was placed on motor and gears, these 12v motors need a good 12v to operate correctly, either shore line plugged in or running your Gen will supply that.
All the links below in my signature have info for your Newmar.