You check e4od with engine off?? I thought practically all autos were checked running in park/neutral and @ operating temp.The transmission is basically a complex hydraulic pump and motor assembly. If there is air anywhere in there, it can cause problems with pressures in the lines. Double check the fluid level. I'm betting its now low. Top it off again, start the motor, run the shifter through all the gears, set it to Neutral, rev the engine, put it in park, shut off the engine and check the levels again. Repeat until the fluid stays full.
Range selector out of adjustment was gonna be my guess. Double check all connections also.could be a MLPS/NSS/Transmission Range Selector issue. but im not sure.