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: Side Air Bags
The side air bags are mounted in the outboard sides of the front seatbacks.
When the air bag crash sensors detect a side impact of greater than moderate
force, the system inflates the side air bag only on the side in which the vehicle
was hit. The side air bag inflates quickly to reduce injury ...
Mazda 6 Service Manual: Technical data
ENGINE
LUBRICATION SYSTEM
Note
The maintenance intervals on scheduled maintenance table (See
SCHEDULED MAINTENANCE TABLE) can only be supported by the use of following
oils.
Recommended engine oil
COOLING SYSTEM
FUEL AND EMISSION CONTROL SYSTEMS
ENGINE ELECTRICAL SYSTEM
...