Around 15 years ago I was in my friends '79 Cutlass Calais, automatic transmission, going down a large hill. He put it in neutral to see how fast he could go while coasting. Probably got up to about 60mph before he put it in gear. We heard a huge clunk and and everythng went dead. I looked down and just yelled "R"!!!!!!! Which was my lame attempt to tell him he put in Reverse. He pulled off to the side of the road and luckily it restarted. He never had any transmission problems with it after that.