Finally got a Magnum, 2005,3.5,AWD

Finally got my first magnum, gotta figure out why my nag1 keeps throwing a P0730 code, then looking into ditching the 3.5 for a 5.7 or 6.1. Trans codes I'm getting from my scanner are P0730 (incorrect gear ratio), P0731 (gear ratio error in 1st), P1637 (TCM INTERNAL-EEPROM PERFORMANCE) Any help would be greatly appreciated, from everything I've seen so far it could be fluid low due to bad o-rings on case connector or bad solenoids oe even a bad TCM. Heeelllppppp!!!