Mike, read the thread "Demco 21K hitch noisy when turning" by sarge. His hitch is destroying itself in 50 miles. Not the same problem as your's....BUT.
Thank you for pointing out that thread. My installer showed me specifically how to adjust the tension on the Autoglide as well as all the places to lube before each use. From reading some of the comments I don't think the thread op has adjusted the tension, nor applied any lube/grease/lithium to his Autoglide. However, thanks to you pointing that out to me, I re-read the manual three times and think I have a pretty good idea of all the adjustments I will need to make tomorrow when I go get my Cyclone!
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I was able to take a much better look at the Pro Series 20k hitch tonight. The slider activation arm seems to have failed at the inner cotter pin hole. Also what surprised me most, is the amount of rust at the point of suspected failure. There shouldn't be any rust on the surface where the seperation occurred, and yet there is...
I'm not a metallurgist but here is my best guess as to what happened. The sliding arm sheared off at th inner cotter pin location. This allowed the hitch to move from a 'locked towing' position to a free sliding position. So while I was only moving at most 3mph, the sudden shift in weight of the hitch sliding to the rear and the the sudden stop when it hit the end of travel caused the hitch to release the pin. This release then dropped the trailer onto my truck, and fortunately with the tailgate up my truck managed to keep the trailer off the ground.
i took several more pictures tonight, but haven't had a chance to upload them. I probably need to dig out my digital camera and get some good macro shots of the arm failure. Not sure my phone camera will provide a high enough resolution to illustrate what I am explaining.