Line Pressure Test

WARNING: This page is about a different car, the 2002 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: 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 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.

This test verifies that the line pressure is within specification.

Connect pressure gauge to line pressure tap.
Start engine and check line pressures. Refer to Fig 1 to see if line pressure is within specification.
Line Pressure Chart

Fig 1: Line Pressure Chart
Courtesy of FORD MOTOR CO.

Clutch Pressure Chart 4.2L and 4.6L

Fig 2: Clutch Pressure Chart 4.2L And 4.6L
Courtesy of FORD MOTOR CO.

Clutch Pressure Chart 5.4L

Fig 3: Clutch Pressure Chart 5.4L
Courtesy of FORD MOTOR CO.
Place the ignition switch in the OFF position. If line pressure is not within specification, check EPC pressure.
Connect pressure gauge to EPC pressure tap.
Start engine and check EPC pressure. Use the line pressure chart for specifications.
If EPC pressure is not within specification, carry out PINPOINT TEST E to diagnose EPC operation. If EPC operation is OK, see the line pressure diagnosis chart for line pressure concern causes.