One problem related to transmission gear slipping has been reported for the 2011 Ford Flex. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2011 Ford Flex based on all problems reported for the 2011 Flex.
From a stop, transmission slipped, banged into 1st (or 2nd gear), did it again around 50 mph, felt like the tranny slipped and then banged into gear. The banging into gear is a violent lurch. Took it to Ford told nothing wrong with vehicle (even though I had prior TSB's on same tranny issues in 01/2011 build cars). Started in 2012, was intermittent until recently and has happened several times over past month.