1. Inspect the dust boot on the drive shaft for cracks, damage, leaking grease, and looseness in the boot band.

2. Inspect the drive shaft for bends, cracks, and wear in the joint or splines.
Joint shaft disassembly/assembly
Drive shaft removal/installationMazda 6 Service Manual: Discharge headlight control unit removal/installation
Caution
Incorrect servicing of the discharge headlight control unit could
result in electrical shock. Before servicing the discharge headlight control
unit, always refer to the Discharge headlight service warnings. (See
DISCHARGE HEADLIGHT SERVICE WARNINGS)
When replacing the discharg ...
Mazda 6 Service Manual: Rear door speaker removal/installation
1. Disconnect the negative battery cable.
2. Remove the rear door trim.
3. Remove in the order indicated in the table.
4. Install in the reverse order of removal.
Rear Door Speaker Installation Note
Attach the speaker with the wiring harness placed in the groove of the door
unit panel.
...