Jerry enjoys sharing his knowledge and also gleaning from others knowledge. This was not invented by Jerry and we do not know where it got started however he has been using this for 25+ years. C900 5 speed transmission, popping out of reverse has been a common problem. It comes from improper use of your clutch. Jambing into reverse breaking the leading teeth off the slider and reverse gear. When backing it will violenty pop out. Here is a procedure to possibly solve your problem without pulling your transmission and replacing reverse gears. Takes an hour of time and a side cover gasket. If your gears look like the ones in these pictures, YOU ARE DONE! Contact Jerry if you need some of these parts or help.