Hard Shifts and Transmission Slips on Lincoln MKZ

Model years 2007-2012 of the Lincoln MKZ using the 6-speed automatic transmission have been known to produce hard shifting and transmission slippage between gears. This is most noticeable when the transmission is hot, but can happen at any time. Note, this transmission is designed to be ‘sealed for life’ meaning the transmission fluid is never meant to be changed.

As many drivers and owners have learned, the issues are caused by problematic software for the transmission or mechanical failures associated with the transmission valve body or shift solenoids.

In order to restore transmission performance while shifting, the manufacturer of the transmission has issued several software updates that should correct the shifting issues. If hard shifts and slippage still exist after the software updates are completed, the transmission must be removed, disassembled, inspected and repaired.

Some technicians have advised replacing transmission fluid at normal intervals, but the manufacturer guidance is to use the original transmission fluid for the entire service life of the vehicle.