You may want to check you slide frames to see if you have any separations like you will see in this thread.
http://www.montanaowners.com/forums/...ad.php?t=55388
You will also see Bingo's Pics of his slide frames, that appear to be in pristine condition.
You will need to pull the slide wipers off the frame if you want to see if the cables are rubbing on the frames which will cause them to fray and break.
I had to investigate this on my own because the unit is out of warranty and the dealer did not want to invest any time into it without a guaranty that Keystone would cover it under warranty.
It appears Keystone has repaired some units out of Warranty for this and other issues, wish you well .