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Line Pressure Test

CAUTION: Do not maintain Wide Open Throttle (WOT) in any gear for more than 5 seconds. If engine RPM exceeds maximum specified stall speed, release accelerator immediately. Clutch or band slippage is indicated.
  1. Connect a pressure gauge to line pressure test port. See Fig 1 . Start engine. Apply service and parking brakes. Check pressure in all gears. See TRANSAXLE PRESSURE SPECIFICATIONS (PSI)  .
  2. If pressure is not within specification, perform QUICK TEST and PINPOINT TEST E. See AUTO TRANS DIAGNOSIS - AX4N ELECTRONIC article. Also perform air pressure checks and service valve body. See AIR PRESSURE TEST.
  3. If line pressure is not within specification after servicing valve body and there are no fault codes present during EEC-V Quick Test procedure, Electronic Pressure Control (EPC) solenoid may have a mechanical fault. Connect pressure gauge to EPC port. Start engine and check pressure at idle and at Wide Open Throttle (WOT). If pressure is not within specification, replace EPC solenoid.
TRANSAXLE PRESSURE SPECIFICATIONS (PSI)

Selector Position @ Idle RPM @ WOT Stall RPM
1997 Models
Line Pressure
"P" (1) 146-171 ---
"P" & "N" 60-84 ---
"R" 78-108 265-328
"OD" & "D" 60-84 208-257
"1" 60-84 208-257
EPC
"P" (1) 45-55 ---
"P" & "N" 10-20 ---
"R" 10-20 70-90
"OD" & "D" 10-20 70-90
"1" 10-20 70-90
1998 Models
Line Pressure
"P" (1) 146-171 ---
"P" & "N" 60-84 ---
"R" 78-108 265-328
"OD" & "D" 60-84 208-257
"3"& "2" 102-138 208-257
"1" 67-138 208-257
"1" (SHO) 84-185 208-257
EPC
"P" (1) 45-55 ---
"P" & "N" 10-20 ---
"R" 10-20 70-90
"OD" & "D" 10-20 70-90
"3"& "2" 30-40 70-90
"1" 15-40 70-90
"1" (SHO) 30-55 70-90
(1) With fluid temperature less than 150°F (65.6°C), before gear engagement.
Fig 1: Identifying Pressure Test Ports
G96G04044Courtesy of FORD MOTOR CO.
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