1. Remove the drain plug with the washer.
2. Drain the oil into a suitable container.
3. Install a new washer and the drain plug.
Tightening torque 40-58 N·m {4.0-6.0 kgf·m, 29-43 ft·lbf}
4. Remove the oil level plug with washer and add nthe specified amount and type of oil through the oil level plug hole until the level reaches the bottom of the oil level plug hole.
Specified oil viscosity All-season: SAE 75W-90
Above 10 ° C {50 ° F}: SAE 80W-90 Capacity (approximate quantity) 2.87 L {3.03 US qt, 2.53 lmp qt}

5. Install a new washer and the oil level plug.
Tightening torque 40-58 N·m {4.0-6.0 kgf·m, 29-43 ft·lbf}
Transaxle oil inspection
Oil seal (differential) replacementMazda 6 Service Manual: Air intake actuator inspection
1. Connect battery positive voltage to terminal D or F and ground to terminal
F or D of the air intake actuator.
2. Verify that the air intake actuator operates as shown below.
If not as specified, replace the air intake actuator.
...
Mazda 6 Service Manual: Oil seal (differential) replacement
1. On level ground, jack up the vehicle and support it evenly on safety
stands.
2. Drain the oil from the transaxle.
3. Remove the front wheels and splash shields.
4. Separate the drive shaft and joint shaft from the transaxle. (See DRIVE
SHAFT REMOVAL/INSTALLATION.) (See JOINT SHAFT REMOVAL/ ...