1995 Toyota 4Runner Weird tranny problem

Transmission problem
1995 Toyota 4Runner 6 cyl Four Wheel Drive Automatic 75k miles

Hello,

After experiencing some slipping and eventualy failure (truck would'nt drive in any gear) I changed the filter and fluid on my 4runners automatic tranny. The pan was pretty clean; no metal fragments just a thin layer of sludge in a couple spots. I did'nt do a complete flush just emptied the pan a couple of times and replaced with new fluid. Since doing that service the car moves, but if you come upon any hill (in Drive) it loses power and it feels and sounds like the engine is lugging. Moving the shift lever to 2nd is even worse---bad engine lugging and zero power. I have to shift down to Low to get up any hill and I live with alot of hills. Low seems to be acting normaly. Does that sound mechanical (bands?) Or electrical (solenoids?)---I know these cars have had solenoid issues.

Appreciate any help,

Hoping its not bands.