The mechanical components of this unit 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, and FOURTH gears,
depending on the vehicle application. ECCC was developed to reduce the possibility
of noise, vibration, or chuggle caused by TCC apply. Typical apply speeds are 49-52 km/h
(30-32 mph) in THIRD gear and 65-73 km/h (40-45 mph)
in FOURTH gear. Full lockup is available at highway speeds on some applications. |
| • | Intermediate/4th and Lo/Reverse friction band assemblies |
| • | Forward, Coast, 2nd, Reverse, and Direct multiple disc clutch assemblies |
| • | Two planetary gear sets: Input and Reaction |
| • | Two roller clutches (Lo and 2nd) |
| • | One control valve assembly |
| • | A final drive and differential assembly |
The electrical components of this unit are as follows:
| • | Two shift solenoid valves, 1-2 and 2-3 |
| • | A Torque Converter Clutch Pulse Width Modulation (TCC PWM) solenoid valve |
| • | A transmission Pressure Control (PC) solenoid valve |
| • | An Automatic Transmission Fluid Temperature (TFT) sensor |
| • | Two speed sensors: Input and Output Speed Sensor |
| • | An Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch
assembly |
| • | An Automatic Transmission Wiring Harness Assembly |
Transmission Adapt Function
The 4T40-E transmission uses a line pressure control system, which has
the ability to continuously adapt the system's line pressure. This compensates
for normal wear of the following parts:
| • | The clutch fiber plates |
The PCM maintains the Upshift Adapt parameters for the transmission.
The PCM monitors the AT ISS sensor and the AT OSS during commanded shifts
in order to determine if a shift is occurring too fast or too slow. The
PCM adjusts the signal from the transmission pressure control solenoid in
order to maintain a set shift feel.
Transmission adapts must be reset whenever the transmission is overhauled
or replaced. In order to reset transmission adapts, select the following:
- Tech 2
- Special Functions
- Transmission Output Controls
- Clear TAPS
