Line Pressure Test

WARNING: If equipped with fire suppression system, refer to FIRE SUPPRESSION SYSTEM article for Important Safety Warnings. Failure to follow this instruction may result in serious personal injury.

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 WOT in any transmission range for more than 5 seconds.

Fig 1: Locating Transmission Pressure Taps

Courtesy of FORD MOTOR CO.

Item	Part Number	Description
1	-	Direct clutch pressure tap
2	-	Forward clutch pressure tap
3	-	Electronic pressure control (EPC) pressure tap
4	-	Intermediate clutch pressure tap
5	-	Line pressure tap

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 the Line Pressure Chart to determine if line pressure is within specification.

LINE PRESSURE CHART

Application	Range	Idle		WOT
Application	Range	EPC	Line Pressure	EPC	Line Pressure
All	P, N	34-276 kPa (5-40 psi)	276-689 kPa (40-100 psi)	N/A	N/A
	OD, 2, 1	34-276 kPa (5-40 psi)	276-689 kPa (40-100 psi)	689-793 kPa (100-115 psi)	1,172-1,586 kPa (170-230 psi)
	R	172-207 kPa (25-30 psi)	483-862 kPa (70-125 psi)	586-655 kPa (85-95 psi)	1,124-2,068 kPa (250-300 psi)

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. Refer to the LINE PRESSURE CHART for specifications.
If EPC pressure is not within specification, go to Pinpoint Test E to diagnose EPC operation. If EPC operation is OK, refer to the Line Pressure Diagnosis Chart for line pressure concern causes.
When the pressure tests are completed, install the pressure tap plugs.
- Tighten to 12 Nm (9 lb-ft).

LINE PRESSURE DIAGNOSIS CHART

Test Results	Possible Source
High At Idle - In All Positions	Wiring harnesses Run Quick Test. Refer to the Introduction - Gasoline Engines article EPC solenoid Main regulator valve
Low At Idle - In All Positions	Low fluid level Control bodies Leakage in pump Damaged gaskets on separator valve Damaged separator plate Restricted inlet filter Case bolts Loose main control valve body EPC solenoid O-ring EPC solenoid bracket Case Sticking main regulator valve Damaged inlet tube seal on inlet filter
Low In Park Only	Valve body Low/reverse servo
Low In Reverse Only	Separator plate Low/reverse servo or valve bodies Reverse clutch
Low In Neutral Only	Valve body
Low In Overdrive Only	Forward clutch Valve body
Low In 1st Position Only	Forward clutch Valve body Low/reverse servo
Low In 2nd Only	Intermediate clutch Valve bodies Forward clutch