sentences:  Noise, vibration, and harshness expertise later found the issue to be destructive harmonics within the transmission and this was remedied with the transmissions later being highly regarded for reliability when properly maintained.Ford would often meet repair costs for these transmissions post-warranty on a goodwill basis.Until the fix, taxi owners would continue to fit reconditioned three-speed "M51" automatics to these cars, until the bell housing design was finally changed in later models preventing this practice.