After some steep loose hill climbs the other day I backed up and lost reverse so I took off forward and got about 50 yards on flat ground and lost forward.(engine and tranny were definatly overheated) so I waited about an hour while I thought about how I was going to get the K5 back down the mountain. I decided see if would go enough to get turned around and it worked fine no slipping...well to make a short story longer it happened 3 more times going down and all I had to do was shut the engine off and restart it right away and it would go again. The fluid level is full and it never really slipped just quit. I'm thinking it might be a sticking valve in the valve body. any ideas?