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: Installation of radio system
If a radio system is installed improperly or if a high-powered type is used,
the CIS and other systems may be affected. When the vehicle is to be equipped
with a radio, observe the following precautions:
Install the antenna at the farthest point from control modules.
Install the antenna fe ...
Mazda 6 Service Manual: Oil seal replacement
1. Drain the ATF. (See AUTOMATIC TRANSAXLE FLUID (ATF) REPLACEMENT.)
Caution
The oil seal is easily damaged by the sharp edges of the drive
shaft splines. Do not let the splines contact the oil seal.
2. Remove the drive shaft. (See DRIVE SHAFT REMOVAL/INSTALLATION.)
3. Remove the oil sea ...