A well-documented and well-known issue with the Mazda 6 built between 2005-2012 is harsh shifting from the 6-speed automatic transmission , and slight slippage between gears. This has been noted as hesitation to accelerate, especially from a stop.
Mainly, software issues have been to blame for these mishaps, but mechanical malfunctions related to shift solenoids and the valve body have also been major causes. Finally, the automatic transmissions in these models are sold as ‘sealed for life’, yet the transmission fluid does not seem to last the complete service life of the vehicle.
Correction of these issues often requires a simple software update, meaning the vehicle only needs to be plugged in, and the transmission controller receives new programming meant to fix these drivability concerns. In cases where this does not correct concerns, the transmission must be removed, inspected, and repaired, possibly requiring a complete rebuild.
To mitigate these issues from escalating to a full transmission rebuild, many technicians recommend replacing the transmission fluid at regular intervals, yet the manufacturer has never offered this guidance.