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OVERDRIVE RANGE, SECOND GEAR

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As vehicle speed increases and other operating conditions are appropriate, the PCM de-energizes the 1 -2 shift solenoid valve in order to shift the transmission to second gear. 1- 2 Shift Solenoid (SS) Valve De-energized (turned OFF) by the PCM, the normally open solenoid opens and signal A fluid exhausts through the solenoid. 2- 3 […]

NEUTRAL – ENGINE RUNNING

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When the gear selector lever is moved to the Neutral position (N) from the Reverse position, the following changes occur to the transmission hydraulic and electrical systems. Manual Valve In the Neutral position, the manual valve blocks the line pressure from entering any other fluid circuits. Reverse and PR fluids exhaust past the manual valve. […]

PARK – ENGINE RUNNING

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With the gear selector lever in the PARK (P) position and the engine running, the line pressure from the oil pump assembly is directed to various components in the valve body and the oil pump. The pressure regulator valve regulates the oil pump output (line pressure) in response to the signal fluid pressure, the spring […]

AUTOMATIC TRANSMISSION INLINE 20-WAY CONNECTOR DESCRIPTION

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Fig. 485: Identifying Automatic Transmission In-Line 20-Way Connector Courtesy of GENERAL MOTORS CORP. The transmission electrical connector is an important part of the transmission operating system Any interference with the electrical connection can cause the transmission to set diagnostic trouble codes or affect proper operation. The following items can affect the electrical connection: • Bent […]

ELECTRONIC COMPONENT DESCRIPTION

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1- 2 and 2-3 Shift Solenoid Valves Fig. 477: View Of 1-2 & 2-3 Shift Solenoid Valve Courtesy of GENERAL MOTORS CORP. The 1-2 and 2-3 shift solenoid valves (also called A and B solenoids) are identical devices that control the movement of the 1-2 and 2-3 shift valves. The 3-4 shift valve is not […]

TRANSMISSION ADAPTIVE FUNCTIONS

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The 4L60-E transmission utilizes a line pressure control system during upshifts to compensate for the normal wear of transmission components. By adjusting the line pressure, the powertrain control module (PCM)/transmission control module (TCM) can maintain acceptable transmission shift times. This process is known as "adaptive learning" or "shift adapts" and is similar to the closed […]

TRANSMISSION COMPONENT AND SYSTEM DESCRIPTION

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The mechanical components of the 4L60-E are as follows: • A torque converter with an electronically controlled capacity clutch (ECCC) This transmission is equipped with an ECCC. The pressure plate does not fully lock to the torque converter cover. Instead, the pressure plate maintains a small amount of slippage, about 20 RPM, in SECOND, THIRD […]

DEFINITIONS AND ABBREVIATIONS

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Throttle Positions Engine Braking A condition where the engine friction is used to slow the vehicle by manually downshifting during a zero throttle coastdown. Full Throttle Detent Downshift A quick apply of the accelerator pedal to its full travel, forcing a downshift. Heavy Throttle Approximately 3/4 of accelerator pedal travel (75 percent throttle position). Light […]

TRANSMISSION GENERAL INFORMATION How to Use This Section

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This section provides the following information: • General diagnosis information on transmissions • Procedures for diagnosing the Hydra-matic transmission When you diagnose any condition of the Hydra-matic transmission, begin with A Diagnostic Starting Point. This procedure indicates the proper path of diagnosing the transmission by describing the basic checks. This procedure will then refer you […]

HOLDING FIXTURE REMOVAL Tools Required

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J 8763-B Holding Fixture and Base. See Special Tools. Fig. 473: View Of J 8763-B Courtesy of GENERAL MOTORS CORP. Removal Procedure Remove the transmission from the J 8763-B. See Special Tools. DESCRIPTION AND OPERATION