[caddojay]

I have the thought that the squre tube "shook" loose from the drive cam over a few trips. I had not heard any unusual noises when going in or out with slide. I believe the collar that holds it to the cam vibrated loose over some time. How much time is unknown. Our unit has been parked since May, and this is the first trip since then. It may have started when we were coming across I-10 from Florida in early May. Lots of bumps! Lots of other bumps coming across I-410 in San Antonio. Obviously, I blame the collar for not holding. Maybe a screw through the tube and cam would be extra insurance. I simply re-installed the collar and put loc-tite on the hex screws that hold the collar. I don't know where I could buy a larger collar with the same interior dimensions, but I would think that a larger collar with more torque on the screws would be beneficial.
The slide stopper was no doubt broken when the slide slid out in an uncontrolled movement. The side under the fridge came all of the way out, forcibly, and the other end came out, but not completely. Therefore, it came out in an movement that was uneven and twisted. The slide stop on the end that was not sheared off was at an unusual angle as if it had been twisted. I have gone back on all of the slide stoppers and added an extra screw in the part of the slide stop that did not have one. Hope this helps others. Again, ours is an electric slide and I have no idea how the hydraulic slides work.