A/T - AODE Intermittent Loss of Torque at 3-4 Upshift
Article No.95-5-15
03/13/95
TRANSMISSION - AODE/4R7OW - INTERMITTENT LOSS OF TORQUE DURING OR JUST AFTER 3-4 UPSHIFT - MAY BE INTERMITTENT
FORD:
1992-95 CROWN VICTORIA
1994-95 MUSTANG, THUNDERBIRD
LINCOLN-MERCURY:
1992-95 GRAND MARQUIS, TOWN CAR
1993-95 MARK VIII
1994-95 COUGAR
LIGHT TRUCK:
1994-95 E-150, F-15O
ISSUE:
There may be an intermittent loss of torque during or just after the 3-4 upshift or in 4th gear on some vehicles. Other gears and shifts are normal. The vehicle may lose power and have engine RPM increase. Normal operation may occur after:
^ The driver pushed the transmission control switch (TCS).
^ The driver moved the shift lever to manual 2nd.
^ The vehicle has coasted to the 4-3 downshift speed.
This may be caused by a hydraulic condition in the transmission or an intermittent signal from one of the powertrain system sensors.
ACTION:
Refer to the following Diagnostic Procedure to determine the correct action for service.
DIAGNOSTIC PROCEDURE
Obtain detailed information about the concern's symptoms from the customer. Under what operating conditions does the concern happen? Is the transmission hot or cold? In what gear or gears does it happen? Does it happen most of the time, some of the time or hardly ever?
Preliminary Checkout Routine
^ Check transmission fluid level and note condition.
^ Check shift linkage adjustment in overdrive.
^ Check for non-factory installed items and verify proper installation.
^ Check line pressure.
^ Perform "Quick Test" both KOEO and KOER.
^ Record and repair all diagnostic trouble codes.
^ Check vehicle wiring for intermittent or open circuits, connectors for proper engagement, damage, corrosion, bent pins and missing or damaged seals.
^ Perform Pinpoint Tests A, D and F in Section 07-01 of the Service Manual and service as required.
Road Test Procedure
Install pressure gauges (0-300 psi) on the forward and direct clutch pressure taps (Figure 3) to monitor and record hydraulic system pressures. Also install the Rotunda New Generation Star Tester (NGS 007-00500), Service Bay Diagnostic System (SBDS 001-00001) or equivalent equipment to monitor and record the following transmission control system inputs/outputs:
^ PCM gear command
^ Throttle position
^ Engine RPM
^ Mass air flow
^ Vehicle speed
^ Transmission fluid temperature
^ OSS sensor voltage
^ PRNDL position
^ TR/MLP sensor voltage
Road test vehicle under the conditions at which the customer described as being present when the concern occurred (i.e., the first shift in the morning, after driving 20-30 minutes, heavy throttle shifts, etc.). If the concern does not occur, let the vehicle sit outside overnight and repeat the test drive with cold transmission fluid. Continue to drive the vehicle until the transmission fluid temperature reaches at least 150~F (65~C). Monitor and record the sensor signals and hydraulic pressures as stated earlier in this article. After completing the test drive, use the following charts (Figures 1 and 2) to help diagnose and correct the customer's concern.
^ Use Chart # 1 if you CAN verify the customer's concern.
^ Use Chart # 2 if you CANNOT verify the customer's concern.
Parts Block
Figure 4
Figure 5
Figure 6
OTHER APPLICABLE ARTICLES: 95-3-6, 95-3-13
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
950515A Perform Transmission 1.3 Hrs.
Diagnosis
950515B Replace MLP/TR Sensor 0.7 Hr.
And Connector
950515C Replace Output Shaft 0.2 Hr.
Speed Sensor
DEALER CODING
BASIC PART NO. CONDITION CODE
7G484 08
OASIS CODES: 501000, 503000, 504000