My son's 1977 Power Wagon 4X4, 360/auto that he got a little over a month ago. He claims he was just driving around and parked it, then went to move it after an hour or so of being parked he had no reverse. I say "he claims" as he is a 17 year old and I am sure he had been showing it off as it has some performance additions to the engine and he has been bragging it up to his friends that have Fords and Chevys. It parks in "park", drop the gear shift down and no reverse but it will start moving forward like it is drive. Moves forward in all gears and shifts. Slowly bring the gear shift back toward park and it will still be going forward when the selector is in reverse and then a little more toward park and you can hear the parking sprag trying to catch. I was just creeping along when trying this. No odd or grinding noises while moving through the shift pattern while parked or moving. So, anything obvious or easy to check? We do have a garage/shop stall and a decent set of tools, but as of now it can get to the transmission shop under its own power. Don't want him to rip into it and then need to tow it to the transmission shop when he is over his head. Plus, where he works part-time just shut down for 2 weeks or more so trying to save some money if he/we can fix it ourselves.