Remove oil filler/level check screw (1).
Remove oil drain plug (2) and drain the oil from the gearbox into a suitable tray.
Remove selector lever (3).
Carefully drive back centering pins (4), from the cover side or casing side, as applicable.
Remove screws (5) securing cover to housing.
Set the gearbox down on its cover.
Caution! Avoid damage to the housing cover and painted surfaces.
Heat the bearing points in the housing to 80...100°C (176...212°F).
Tap lightly with a plastic-faced hammer to disengage the housing.