dbldoug theres not much a very unknowledgable person can do to a automatic transmission i dont know if its a 350 or 400 but both acts the same except the 350 has the kick-down cable, but that only effect the passing gear anyway. if you wont to try something that might help, you can change the filter, and or the modulate valve (the can looking thing with the vac. line going to it). other wise its going ot be on the inside of the trans. and then it will have to be rebuilt or replaced with a used one. you need to go to another shop than the one that said he might could fix it. the convertor might do that but its to much of a job to take the chance and its no way of knowing without replacing it. it sounds like the front pump but if its slipped the clutches any, they will need to be replaced also. change the fluide and filter and if that dont fix it youll need to get a used one or get some one to rebuild yours.