Subaru Automatic Transmissions (4EAT) Phase II Module 302 – Technicians Reference Booklet

The 4EAT Phase 2 (introduced on 1999 Model Year vehicles) provides the same type of electronic control used by prior model year vehicles and shares many of the same diagnostic procedures, however there have been internal and external changes that require this 4EAT to be viewed as an entirely new automatic transmission. Additionally, beginning with the 2001 model year, an enhancement to the all wheel drive transfer section was introduced. This enhancement, Variable Torque Distribution (VTD), is covered in this reference booklet starting on page 9.

Externally, the number of bolts in the torque converter housing area have increased to match the increase in the number of bolts in the bell housing of the engine. The use of an external canister type oil filter has been adopted which requires no scheduled maintenance.

Three speed sensors are now located on the outside surface of the transmission case reading rotational speeds of internal components improving transmission characteristics.

Internally the Brake Band and Servo Mechanism have been deleted and in its place an additional clutch pack is used as a holding member for second and fourth gear. Also the remaining clutch assemblies and the valve body have been redesigned requiring new disassembly and assembly procedures.


  • Slide Sequence
  • Introduction
  • Disassembly
  • Variable Torque Distribution (VTD)
    • 4EAT Phase 2 Disassembly Continued
  • Servicing the Oil Pump
  • Servicing the High and Reverse clutch
  • Servicing the Planetary Gear Assembly and Low Clutch
  • Hydraulic Control
  • Line Pressure
    • Lock up Engagement
    • Lock up Release
    • 1st gear
    • 2nd Gear
    • 3rd Gear
    • 4th Gear
  • TCM Control
    • Normal Shifting
    • Slope Control
    • Control at Low Temperature
    • Control During ABS Operation
    • Engine Over Speed Prevention Control
  • Timing Control
  • Low Clutch Timing Control
    • Engine Torque Control
    • Learning Control
    • Reverse Inhibit Control
    • Engine Brake Control
  • Self Diagnosis
    • Failsafe Function
    • 2002 Impreza 4EAT Phase 2 Enhancements “Chopper Voltage Signal”

Language: English
Format: PDF
Pages: 36

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