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: Front door glass removal/installation
1. Operate the front door glass so that the distance from the top of the
front door glass to the upper part of the rear beltline molding is 210 mm
{8.3 in}.
2. Disconnect the negative battery cable.
3. Remove the front door trim.
4. Remove the hole cover.
5. Remove the screws.
6. Insert ...
Mazda 6 Service Manual: Cargo compartment light switch inspection
1. Remove the liftgate lower trim. (See LIFTGATE LOWER TRIM
REMOVAL/INSTALLATION)
2. Disconnect the cargo compartment light switch connector.
3. Inspect for continuity between the cargo compartment light switch
terminals using an ohmmeter.
If not as specified, replace the liftgate lock.
...