I have a 1990 Toyota Camry with 235k on it. Even though the car is old with many miles it has ran perfectly fine the last 3 years I have owned it. The other day however it would not go into reverse. Also the light that is on the dash board showing the car is in reverse didnt come on. I shifted the gears back and forth from d to n d2 d1 etc. And nothing happened so I had to push the car out of the parking spot. Then in drive the car drove and shifted just fine with no slipping, hesitations or anyhting. The next time I tried to put it in reverse it did the same thing but when I turned the car off and restarted it the car went into reverse. I drove the car like this for a couple days and besides reverse the car drove normally. Then today when I was driving the car seemed to slip out of drive and wouldnt move no matter how much gas I gave it. I towed the car home and checked the transmission fluid. It was brownish, slightly low and a little burnt smelling. I added some fluid and the car drove 1-2 miles before it "slipped" out of gear and wouldnt go back into gear again. When it was in gear it shifted fine like it always has and seemed to run just as it did before. Ive tried driving it 4-5 times and it drives fine for a while put eventually slips out of gear. However when I turn the car off and on it will go into gear for a few feet and then slip out. Also the lights on the dash that show which gear the car is in will not light up except d2 and d1. Park reverse neutral and drive will not and previously they did. I was wondering if I do need a new transmission, a flush, new filter, solenoid, or perhaps some type of sensor because when its cold it will engage in the correct gear it shifts and works perfect but for some reason once warm it just slips out and wont move until the car is cold or I turn it off and on again.