I thought that the way to check the tranny fluid level is to leave the car in idle and the gear in park and when the car is at operating temperature. I still say it is the clutches in the tranny that slip when it gets warm or the pump has issues.

__________________
01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow