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: Starting the Engine
WARNING
Radio waves from the key may affect medical devices such as pacemakers:
Before using the key near people who use medical devices, ask the medical device
manufacturer or your physician if radio waves from the key will affect the device.
NOTE
The key must be carried because the key c ...
Mazda 6 Service Manual: Oil leakage inspection
Use either of the following procedures to identify the type of oil that
is leaking:
Using UV Light (Black Light)
1. Remove on the engine or transaxle.
Note
Referring to the fluorescent dye instruction manual, mix the
specified amount of dye into the engine oil or ATF (or transaxle ...