Impreza 2.5 RS Sedan AWD F4-2.5L SOHC (2002)
4. Using a screwdriver, pry the retaining ring off.
5. Extract the shaft from the front casing.
6. Remove the parts listed from the front casing.
CAUTION: Discard old seal washer; replace with a new one.
7. Pry the oil seal off using a screwdriver.
CAUTION: Be careful not to scratch inner surface of casing.
8. Remove the pressure switch.