Park ,drive, shifter loose also will only drive in 2nd. Gear stalls doesn't shift

Sounds like an internal transmission concern, mechanically. These 5R55 transmissions have some characteristic valve body and solenoid issues -- but it's usually beyond in chassis repair...and 20 years later, almost assuredly. All you can really do is ensure the transmission fluid is full and clean. I don't think you can even do that yourself, as there is a "fill plug" and "drain plug" but no dipstick on most of these. See a local shop near you that can assist. That other shop could give you diagnostic advice or steps forward should you need a bigger repair. www.repairpal.com/repair-shops