1993 park avenue ultra help

[Jmona17]

motor starts to slip around 1500 rpm, either at low speed or going up hill. Does this similarly at high speed (65-75) when in overdrive around 2000 rpm. Rmps jump up and down, and the vehicle feels like it is having trouble. goes away if you give it some gas. Occasionally stalls when backing up and then shifting into drive right after starting. Replaced transmission modulator valve and put new trans fluid in not long ago. also, occasionally makes scraping sound when turing hard and accelerating (probably unrelated). Whats wrong? thanks

 

[MelsRegal]

1. How many miles on the transmission?
2. When you changed the fluid did you replace the filter?