2001 Subaru Forester BaseFACTORY OEM SERVICE PROCEDURE

Oil Pump: Function

  • The automatic transmission fluid (ATF) is drawn through the oil strainer mounted under the control valve ASSEMBLY, and is routed to the transmission case, to the oil pump housing, and to the oil pump cover. It then goes to the suction port.
  • As the inner rotor rotates, the outer rotor also rotates. This motion causes ATF to be sucked up through the suction port and discharged under pressure from the discharged port.
  • The discharged ATF flows from the oil pump cover to the oil pump housing. It then goes to the transmission case, the control valve and to the regulator valve, thus serving as hydraulic oil and lubricating oil for the torque converter clutch, valves, clutch.
  • As engine speed increases, the delivery rate of the trochoid pump also increases.
    Fig 1: Oil Pump Schematic
    G02147120
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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