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Line Pressure Test

Fig 1: Locating Line Pressure Tap
G03443485Courtesy of FORD MOTOR CO.
CAUTION: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If line pressure is low at stall, do not carry out the Stall Speed Test or further transmission damage will occur. Do not maintain wide-open throttle (WOT) in any transmission range for more than five seconds or transmission damage may occur.
NOTE: Carry out shift linkage check prior to carrying this test; refer to TRANSAXLE/TRANSMISSION EXTERNAL CONTROLS .

This test verifies the line pressure is within specifications.

  1. Connect the Transmission Fluid Pressure Gauge to the line pressure tap.
  2. Start the engine and check the line pressures. Refer to the LINE PRESSURE CHART  to determine if the line pressure is within specification.
  3. If the line pressure is not within specifications, carry out On-Board Diagnostics and Go To PINPOINT TEST E  air pressure check, and clean, inspect and install a new main control system or pump as required.
LINE PRESSURE CHART

Gear Line Pressure - Idle Line Pressure - Stall
kPa psi kPa psi
P, N 345-448 50-65 - -
R 483-690 70-100 1,689-2,000 245-290
(D), 2 345-448 50-65 1,138-1,276 165-185
1 483-690 70-100 1,207-1,448 175-210
LINE PRESSURE DIAGNOSIS CHART

Low at Idle in All Ranges High at Idle in All Ranges
Check for low fluid level, restricted inlet filter, loose main body, solenoid body or accumulator body-to-case bolts, excessive leakage in pump, case, control bodies, sticking main regulator valve, damaged filter assembly and seal, damaged gaskets or valve body separating plate. Check the main regulator valve, solenoid body and wiring harness. Run the Quick Test referred to in the Diagnostic portion of this article.
Low Only in 
P R N (D) 2 1
Check valve bodies 7A100 Check separator reinforcing plate, coast clutch, low/reverse clutch or direct clutch. Valve bodies 7A100, 7G422 Check valve bodies 7A100 Check forward clutch. Valve bodies 7A100, 7G422 Check forward clutch, coast clutch or intermediate clutch, band, servo assembly. Valve bodies 7A100, 7G422 Check forward clutch, low/reverse clutch or coast clutch. Valve bodies 7A100, 7G422