Two problems related to differential unit have been reported for the 2003 Mercury Grand Marquis. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Mercury Grand Marquis based on all problems reported for the 2003 Grand Marquis.
Paint peeling whine from real differential.
Rear axle bearing failure on 2003 Mercury Grand Marquis. Pe4010. The axles are improperly heat treated and fail due to normal loads. This car is not a police vehicle. There is a clear defect in the axles of all similar body styles.