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: Dual proportioning valve replacement (without abs)
1. Remove in the order indicated in the table.
2. Install in the reverse order of removal.
Dual Proportioning Valve Installation Note
Install the dual proportioning valve so that the R mark faces the left side
of the vehicle.
...
Mazda 6 Service Manual: Headlights
Turn the headlight switch to turn the headlights and other exterior lights on
or off. When the lights are turned on, the lights-on indicator light in the instrument
cluster turns on.
NOTE
If the light switch is left on, the lights will automatically switch
off approximately 30 seconds ...