Selonoid replaced at 20K and acting up at 50k. Had many service flushes with the same fluid replaced. Shifts normal in cool weather, but hard shifts stop and go when motor temp raises to 3/8 on temp gauge. Can anything besides selonoid replacement help?
Instead selonoids, can heat,shift points, or heat fluid viscosity be the problem on 2000 Buick Century
Do you have any pending codes in the ECU? What solenoid was replaced? Which shift is still too firm? Might be time for a remanufactured transmission.