Special Testing Procedures

Engine Idle Speed Check

Refer to the Powertrain Control/Emissions Diagnosis Manual OBDII for the appropriate procedure.

Line Pressure Test

 CAUTION: Perform line pressure test prior to performing stall speed test. If line pressure is low at stall, do not perform stall speed test or further transmission damage will occur. DO NOT MAINTAIN WIDE-OPEN THROTTLE in any transmission range FOR MORE THAN FIVE SECONDS.

 CAUTION: Transmission Tester MUST BE REMOVED from the transmission and the vehicle harness reinstalled to verify these pressures.

This test verifies that the line pressure is within specification.

1. Connect pressure gauge to line pressure tap.

   

2. Start engine and check line pressures. Refer to the following chart for specifications.

3. If line pressure is not within specification, check EPC pressure.

4. Connect pressure gauge to EPC pressure tap.

   

5. Restart engine and check EPC pressure. Refer to the preceding chart for specifications.

6. If EPC pressure is not within specification, perform Pinpoint Test E to diagnose EPC operation. If EPC operation is OK, refer to Line Pressure Diagnosis Chart for line pressure concern causes.

   Line Pressure Diagnosis Chart

   

Stall Speed Test

 WARNING: APPLY THE SERVICE AND PARKING BRAKE FIRMLY WHILE PERFORMING EACH STALL TEST.

 CAUTION: Perform Line Pressure Test prior to performing Stall Test. If the line pressure is low at stall, do not perform Stall Test or further transmission damage will occur.

The stall speed test checks torque converter clutch operation and installation, the holding ability of the forward clutch, reverse clutch (the low-reverse bands), the planetary one-way clutch, and engine performance.

Conduct this test with the engine coolant and transmission fluid at proper levels and at normal operating temperature.

Apply the service and parking brake control (2780) firmly for each stall speed test.

1. Use a grease pencil to mark the following stall speed rpm on the dial of a tachometer.

   STALL SPEED RPM

   Engine/Application	RPM
   5.0L F-150	2142-2530

2. Connect tachometer to engine.

3. NOTE: If the rpm recorded by the tachometer exceeds the maximum limits given in the preceding chart, release the accelerator pedal immediately because clutch or band slippage is indicated.

   In each of the following ranges: D, 2, 1, R, press the accelerator pedal to the floor and hold it just long enough to let the engine get to wide-open throttle. While making this test, do not hold the throttle open for more than 5 seconds at a time.

4. Note the results in each range.

5. After each range, move the selector lever to NEUTRAL and run the engine at 1000 rpm for about 15 seconds to cool the torque converter (7902) before making the next test.

6. Refer to the following chart for corrective actions.

   STALL SPEED DIAGNOSIS CHART

   Selector Position	Stall Speeds High	Stall Speeds Low
   (D)	Planetary One-Way Clutch	—
   (D), 2 and 1	Forward Clutch or Intermediate Clutch	—
   (D), 2, 1 and R	Perform Pressure Test	Torque Converter Stator One-Way Clutch or Engine Performance
   R	Reverse Clutch or Low Reverse Band or Servo	—

   
   

Air Pressure Tests

Test Procedures

A NO DRIVE condition can exist, even with correct transmission fluid pressure, because of inoperative clutches or bands. An ERRATIC SHIFT can be located through a series of checks by substituting air pressure for fluid pressure to determine the location of the malfunction.

Follow the procedure to determine the location of the inoperative clutch or band by introducing air pressure into the various test plate passages.

NOTE: Use only dried, regulated (276 kPa [40 psi] maximum) air pressure. Apply air to the appropriate passage(s). A dull thud should be heard when the clutch or band applies. There should be no hissing sound when the clutch or band is fully applied.

Cover the vent hole in the test plate with a clean, lint-free shop towel to prevent spray when the air is applied. Plugging the vent hole during testing will result in inaccurate results.

1. Drain transmission fluid and remove the transmission fluid pan.

2. Remove the main control and gasket.

3. Install Transmission Test Plate T92P-7006-A and gasket. Tighten bolts to 10-12 Nm (7.5-8.5 lb-ft).

4. NOTE: Do not apply air to the test plate vent hole.

   Apply air to the appropriate clutch port (refer to diagram). A dull thud may be heard or movement felt when the clutch is applied or released. If clutch seals or check balls are leaking, a hissing sound may be heard.

Reverse Clutch:

A dull thud can be heard when the reverse clutch piston (7D402) applies. In addition, movement of the reverse clutch drum (7D044) may also be detected.

Forward Clutch:

A dull thud can be heard or movement of the clutch piston (7A262) can be felt on the case (7005) as the clutch piston is applied.

Intermediate Clutch Cylinder:

A dull thud can be heard or felt when the intermediate clutch piston (7E005) applies.

Direct Clutch Cylinder:

A dull thud should be heard or felt on the driveshaft if the clutch is operating.

Overdrive Servo:

Operation of the band is indicated by the tightening of the band around the reverse clutch drum. The O/D servo will return to the release position as a result of force from the overdrive servo piston return spring (7F201). Also, when the servo returns to the release position, a thud can be felt on the O/D servo retaining ring. The band will then relax.

Service Tool Plate

Low-Reverse Servo:

A dull thud can be heard when the low-reverse band tightens around the planetary assembly drum surface. Also, movement of the ring gear can be detected.

2-3 Accumulator:

The accumulator piston (7F251) should unseat. This can be detected by inserting a metal rod into the 2-3 piston hole. When the accumulator piston unseats, the rod will move. Also, a thud can be heard when the accumulator piston applies.

Air Pressure Test Results

If the servos do not operate, disassemble, clean and inspect them to locate the source of the concern.

If air pressure applied to the clutch passages fails to operate a clutch, or operates clutches simultaneously, inspect the fluid passages in the case.

If air pressure applied to the accumulator fails to operate an accumulator, remove and inspect case passages and piston.

Direct Clutch Pressure Test

The direct clutch pressure test will diagnose a low-pressure condition or leakage in the direct clutch circuit. A difference of 103 kPa (15 psi) or more between direct clutch pressure and line pressure (read at the forward clutch pressure tap) will prevent a normal 3-4 shift.

1.  CAUTION: Pressure gauges affect the shift quality of the transmission. Care should be taken not to accelerate or decelerate rapidly. Possible transmission failure could result.

   Attach 0-2000 kPa (0-300 psi) pressure gauges to the forward clutch pressure tap. Gauges must be accurate enough to distinguish a 103 kPa (15 psi) difference. (If this test is done in conjunction with a line pressure test, pressure gauges will be attached to all pressure taps.) Have sufficient flexible hose to read the gauges in the vehicle.

2. Drive the vehicle. When pressure is applied to the direct clutch, note the difference between the pressure read at forward clutch pressure tap and the direct clutch pressure.

3. If the difference in pressure is less than 103 kPa (15 psi), the direct clutch circuit is OK.

4. If the difference is greater than 103 kPa (15 psi), there could be a leak in the direct clutch pressure circuit. If the difference does not exceed 103 kPa (15 psi), the gauges on the line pressure and direct clutch pressure can be switched to confirm that gauge calibration difference is not the cause.

Shift Linkage Check

NOTE: Check for a misadjustment in shift linkage by matching the detents in the transmission range selector lever with those in the transmission. If they match, the misadjustment is in the indicator. Do not adjust the shift linkage.

This is a CRITICAL adjustment. Be sure the (D) detent in the transmission corresponds exactly with the stop in the steering column tube (3514). Hydraulic leakage at the manual control valve can cause delay in engagements and/or slipping while operating if the linkage is not correctly adjusted. Refer to Section 07-05 for shift linkage adjustment.