1. Verify that the joint shaft is not twisted or cracked.
2. Turn the joint shaft by hand and verify that the bearing rotates smoothly and freely.

Drive shaft
Joint shaft removal/installationMazda 6 Service Manual: Shift Gear (Shifting) Speed Limit
For each gear position while in the manual mode, the speed limit is set as follows:
When the selector lever is operated within the range of the speed limit, the gear
is shifted.
Shift up
The gear does not shift up while the vehicle speed is lower than the speed limit.
Shift down
The gear d ...
Mazda 6 Service Manual: Mazda Radar Cruise Control (MRCC) (Some models)
The Mazda Radar Cruise Control (MRCC) system is designed to maintain headway
control*1 according to the vehicle speed using a radar sensor (front) to detect
the distance to a vehicle ahead, and by presetting the vehicle speed between 30
km/h (19 mph) and 145 km/h (90 mph), the driver is freed ...