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: Cruise Control (Some models)
With cruise control, you can set and automatically maintain any speed of more
than about 25 km/h (16 mph).
WARNING
Do not use the cruise control under the following conditions: Using
the cruise control under the following conditions is dangerous and could result
in loss of vehicle control.
...
Mazda 6 Service Manual: Front door key cylinder removal/installation
1. Remove the front door unit.
2. Remove the cover, then remove the bolt.
3. For protector-equipped vehicles, pull out the protector tab from the latch
and remove the protector.
4. Disconnect the rod.
5. Remove the front outer handle.
6. Turn the key cylinder in the direction indicated by ...