To paraphrase, Ken said that he heard a loud noise and his kitchen slide out stopped retracting. When he checked it out, he discovered that the four mounting bolts of the kitchen slide-out motor had broken out of the housing. In short, further investigation and some discussions with some RV technicians led him to conclude that the bolts became loose and the high motor torque cased the casing to crack - resulting in the other motor mounts breaking. He checked all of his other slide out motors and found that they were all loose.
I didn't see Ken's post until about a week ago. I read the replies to his post and just about everyone who checked their own rig found loose bolts. Even though Ken was posting about a Newmar coach, some responders said that other manufacturer's rigs also had the problem (Monaco and Entegra were specifically mentioned). Needless to say, I grabbed my ratchet set and headed out to investigate.
What I found surprised me. While I didn't have any loose bolts, every one of the 16 bolts in my 4 electric slide out motor mounts needed tightening. I don't own a torque wrench, so I just "hand" tightened them without over-tightening.
The last thing you want with your slide outs is a problem like Ken experienced, so it's important that you periodically check to ensure that your motor mount bolts aren't loose. Some people suggested various methods to prevent it using things like Loctite. For me, for now, I'm just adding a periodic check to my calendar.
The motors are usually accessed by opening a bay door under your slide and looking up to see a long rod with a motor on it (see photos above). I have a 2015 Dutch Star. The kitchen slide out has one motor, the bedroom has one, and the 27' full-wall slide has two. Each of the motors has four mounting bolts.
The kitchen and full-wall slides had easily accessible motors. The bedroom slide motor had to be accessed by raising the bed, removing a single screw from the rear (nearest the headboard) carpeted "flooring" under the bed, and contorting a bit to reach it.
Thanks to Ken for posting his article, and to everyone who responded with great photos and tips. I highly recommend you read his IRV2 post titled "Own A Newmar With Electric Slide Outs... Read This!"
Pick up your tools and go find your motors! They're easy to tighten - and you may end up saving yourself a lot of time, aggravation, and money.
[Update! It's mid-June 2017 and I'm at NIRVC in Lawrenceville, GA. When I arrived for other service, the service advisor told me that Newmar has a recall for these. They have replaced the standard nuts with Loctite's on all of my slide motor mounts.]