LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 2005 >> Excursion 5.4 L, 4WD >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission - 4R100 >> Diagnosis And Testing >> Special Testing Procedures >> Line Pressure Test >> Notes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Line Pressure Test: Notes

Fig 1: Locating Line Pressure Tap
G03908219Courtesy 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 in any transmission range for more than 5 seconds or transmission damage may occur.
NOTE: If the Transmission Tester is installed it must be removed prior to carrying out the test.
NOTE: If equipped, turn the power take-off (PTO) unit off for correct test results. For a description of PTO operation, Refer to TRANSMISSION ELECTRONIC CONTROL SYSTEM  in this article.
NOTE: Carry out shift linkage check prior to carrying out this test; Refer to AUTOMATIC TRANSAXLE/TRANSMISSION EXTERNAL CONTROLS .

This test verifies the line pressure is within specifications.

  1. Connect the 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.