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Home >> Ford >> 2010 >> Taurus SE >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission - Automatic Transaxle/Transmission >> Diagnosis And Testing >> Special Testing Procedures >> Line Pressure Test

Line Pressure Test

Fig 1: Identifying Line Pressure Tap And Transmission Fluid Drain Plug
G06067653Courtesy of FORD MOTOR CO.
ITEM DESCRIPTION

Item Part Number Description
1 7A010 Line pressure tap
2 7A010 Transmission fluid drain plug
NOTE: Carry out the Line Pressure Test  prior to carrying out the Stall Speed Test . If the line pressure is low at stall, do not carry out the Stall Speed Test or further transaxle damage will occur. Do not maintain Wide Open Throttle (WOT) in any transaxle range for more than 5 seconds.
NOTE: Do not mistake the transmission fluid drain plug for the line pressure tap plug or the transmission fluid will have to be refilled.

This test verifies that the line pressure is within specification.

  1. Connect the Transmission Fluid Pressure Gauge to the line pressure tap.
  2. Start the engine and check the line pressures see the line pressure chart to determine if the line pressure is within specification.

    Line Pressure Chart 

    LINE PRESSURE CHART

    Gear Line
    Pressures at Idle (1)
    P 372-413 kPa (54-60 psi)
    R 689-724 kPa (100-105 psi)
    N 372-413 kPa (54-60 psi)
    D 579-600 kPa (84-87 psi)
    L 579-600 kPa (80-90 psi)
    Pressure at Wide Open Throttle (WOT) Stall (1)
    P 372-413 kPa (54-60 psi)
    R 1,724-2,068 kPa (250-300 psi)
    N 372-413 kPa (54-60 psi)
    D 1,655-1,724 kPa (240-250 psi)
    L 1,655-1,724 kPa (240-250 psi)
    (1) All pressures are approximate.
  3. If the line pressure is not within specification, Go To PINPOINT TEST A  to diagnose the Line Pressure Control (LPC) operation. If LPC  operation is OK, see the LINE PRESSURE DIAGNOSIS CHART  for line pressure concern causes.
  4. When the pressure tests are completed, install the line pressure tap plug.

Line Pressure Diagnosis Chart 

LINE PRESSURE DIAGNOSIS CHART

Test Results Possible Source
HIGH at IDLE - ALL RANGES Wiring Harnesses Line Pressure Control (LPC) Solenoid
Main Regulator Valve
LOW at IDLE - ALL RANGES Low Fluid Level Fluid Inlet Filter/Seal Main Control Body Cross Leaks Gaskets Pump Separator Plate
LOW in Park ONLY Valve Body
LOW in Reverse ONLY Separator Plate Reverse Clutch Valve Body Forward Clutch
LOW in Neutral ONLY Valve Body
LOW in O/D  ONLY Forward Clutch Valve Body
LOW in Drive ONLY Forward Clutch
LOW in Manual 1st ONLY Forward Clutch Valve Body