My Fleetwood hangs in first till about 19mph then shifts somewhat harsh. If you are accelerating and slightly lift off the gas around 15 mph it will smoothly shift. I’ve replaced the ac***ulator which had a broken spring, servo, TPS , and IAC. It’s gotten better but still there. The other shifts are good. For the life of me I can’t figure it out. Could this be a shift solenoid issue? Car has 190k so maybe it’s time for a rebuilt but the fact that if you ease off the gas it will shift just fine.

93 Fleetwood Brougham