Want to pass on a problem that developed in our 2000 3555RL Montana. Our living room slideout has given us a little trouble from the time the rig was purchased new. Twice the "T" connector in the hydraulic line broke and it was first replaced under extended warranty and the second time I replaced it myself (learned from watching).
Then, on December 13, 2004, in Blythe, CA my wife was extending the slideouts and she heard a loud cracking sound. When she went outside and looked, she found that the bolts holding the slideout room to the slideout mechanism had pulled out of the flooring and the slideout mechanism was all the way out while the room had only gone out about six inches.
Needless to say we were quite dismayed. Keystone directed us to take it to Beaudry RV in Tucson, AZ. So I purchased some 2x4's and braced the room so it wouldn't fall out and made our way to Tucson where we are presently. It is being repaired now. We've been quoted at about $1500. Hopefully the metal siding stuff will be repaired well enough so that it will still look pretty good.
Thanks to Beaudry RV for getting us in without an appointment. We've been treated very well -- possibly because they'd like to sell us a new one. But, we like the one we have and we have it modified to our liking and don't want to start over again.