Hit a major cold snap here. Jeep ran fine until we hit -30. Starts fine, seems to go into gear. Park brake feels like it is releasing. Have it in four high, transfer case will not go into either four low or two wheel drive. It's a 2002 sport, just replaced the trans fluid with redline mtl. Haven't done the transfer case or diff fluids yet. It revs up normally but once in gear it will big down and die without moving. Not sure what to check. Any advice would be appreciated