Toyota Repair: 98 Lexus ES300 Tranny problems!, friction material, tranny problems

Question
I have a 98 ES300 with about 230,000 miles on it. Recently, i was driving down our local highway and the transmission seemed to slip (rpms jumped as if it were in neutral). After stopping on the side of the road, the check engine light and the TRAC light both blinked a few times. I had the car towed to a shop and a week later, I was told that the transmission filter was clogged, "runs like a new car".. (1 month later).. I put the car into reverse and rpms drop and the car stalls out. restart and everythings fine. as i accelerate onto the highway, when shifting from first to second, and second to third, rmps jump up, followed by a deep clunk and the gears catching! What is wrong with my car? Any help will be appreciated!

Answer
At that mileage it's probably a transmission problem, if the filter/pickup screen was clogged it had to be clogged with something that came from inside the transmission which is usually either metal particles from worn hard parts or friction material from clutches. It sounds to me like there is a major transmission problem.