Transmission Component and System Description

The mechanical components of this unit are as follows:
- A torque converter with a Torque Converter Clutch (TCC)
- A drive link assembly
- 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 sprag clutch
- One vane type oil pump
- 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 seals
- The springs

The PCM maintains the Upshift Adapt parameters for the transmission The PCM monitors the A/T ISS sensor and the A/T 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:
1. Tech 2
2. Special Functions
3. Transmission Output Controls
4. Clear TAPS