Bws_4Life

I Have A 92 Lexus Ls400 And when i drive it for a while it will slip out of gear ..it shifts all good and smoth but then it just is like its in nutrel i changed the transmission fuild and cleaned the fillter and its still dose it....and some times when i turn my lights on my reverse light comes on and its gets stuck in a low gear and wont shift out and my engine check light and a few other lights wont come on...............................anyone know what is rong with it?