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: Interior Care
WARNING
Do not spray water into the vehicle cabin: Spraying water into the
vehicle cabin is dangerous as electrical devices such as the audio and switches
could get wet resulting in a malfunction or vehicle fire.
NOTE
Do not wipe the interior using alcohol, chlorine bleach, or organic solv ...
Mazda 6 Service Manual: Contact Authorized Mazda Dealer and Have Vehicle Inspected
If any of the following warning lights or the indicator light turns on/flashes,
the system may have a malfunction. Contact an Authorized Mazda Dealer to have your
vehicle inspected.
...