Diagnostic procedure
Mazda 6 Service Manual: Rear oil seal
REAR OIL SEAL REPLACEMENT
1. Remove the flywheel. (MTX) (See CLUTCH UNIT REMOVAL/INSTALLATION)
2. Remove the drive plate. (ATX) (See DRIVE PLATE REMOVAL/INSTALLATION)
3. Remove in the order indicated in the table.
4. Install in the reverse order of removal.
Rear Oil Seal Installation Note
...
Mazda 6 Service Manual: Manually Shifting Down
You can shift gears down by operating the selector lever or the steering shift
switches (some models).
M6 → M5 → M4 → M3 → M2→ M1
Using selector lever
To shift down to a lower gear, tap the selector lever forward (-) once.
Using steering shift switch (Some model ...