Automatic Transmission/Transaxle: Description and Operation
GENERAL DESCRIPTIONControl System Diagram
4L30-E Control System Diagram:
Electronic Control Diagram
Electronic Control Diagram:
Transmission Cross Section
4L30-E Transmission Cross Section:
The 4L30-E is a 4-speed fully-automatic transmission. It uses a microcomputer as a control unit to judge running conditions, including throttle opening rate and vehicle speed. It then sets the optimum shifting point so that best driving performance can be achieved.
In addition, the built-in shift mode select function can select three shift modes according to the driver's preference.
- Normal mode - Normal shift pattern.
- Winter mode - Starts in 3rd gear to reduce slippage on ice or snow.
- Power mode - Has a delayed upshift for when more powerful acceleration is required.
Also, the built-in fail-safe function assures driving performance even if the vehicle speed sensor, throttle signal or any solenoid fails.
The self-diagnostic function conducts diagnosis in a short time when the control system fails, thus improving serviceability.
4L30-E FEATURES
The major features of 4L3O-E are as follows:
- A compact structure consisting of 2 sets on planetary gears and flat torque converter.
- Electronic control selects the optimum shift mode according to driving conditions.
- Electronic control maintains the optimum hydraulic pressure for clutch, band brake as well as transmission so that shift feeling is improved.
- Two sets of planetary gears reduce friction on power train. Also, a lock-up mechanism in the torque converter reduces fuel consumption.
- Wide gear ratio and high torque rate of torque converter provide excellent starting performance.
SHIFT CONTROL
The transmission gear is shifted according to the shift pattern selected by the driver. In shifting gears, the gear ratio is controlled by the ON/OFF signal using the 1-2/3-4 shift solenoids and the 2-3 shift solenoid.
BAND APPLY CONTROL
The band apply is controlled when in the 3-2 downshift (engine overrun prevention) and the garage shift (shock control). The band apply solenoid is controlled by the signal from the Pulse Width Modulation (PWM) to regulate the flow of the oil.
TORQUE CONVERTER CLUTCH CONTROL
The clutch ON/OFF is controlled by moving the converter clutch valve through shifting Torque Converter Clutch (TCC) solenoid using the ON/OFF signal.
LINE PRESSURE CONTROL
The throttle signal allows the current signal to be sent to the force motor. After receiving the current signal, the force motor activates the pressure regulator valve to regulate the line pressure.
ON-BOARD DIAGNOSTIC SYSTEM
Several malfunction displays can be stored in the Transmission Control Module (TCM) memory, and read out of it afterward. The serial data lines, which are required for the testing of the final assembly and the coupling to other electronic modules, can be regulated by this function.
FAIL-SAFE MECHANISM
If there is a problem in the transmission system, the TCM will go into a "backup" mode. The vehicle can still be driven, but the driver must use the gear lever to shift gears.
TYPICAL OPERATING PARAMETERS
Torque Converter Clutch (TCC) Application Conditions:
a) Engine coolant temperature must be above 68°F (20°C).
b) 3.1L RODEO & 3.2L TROOPER MODELS PRIOR TO 1992 model: Engine coolant temperature must be above 113°F (45°C).
c) FOR 1992/93 RODEO & TROOPER MODELS ONLY: Engine coolant temperature must be above 158°F (70°C). TCC is ON in 2ND gear during kickdown operation when engine coolant temperature is above 158°F (70°C). Also, TCC is always ON in 2ND, 3RD & 4TH gear when transmission oil temperature is above 284°F (140°C).
"Check Trans" Light:
FOR 1992/93 RODEO & TROOPER MODELS ONLY: In addition to its diagnosis-related function, the "CHECK TRANS" light will be constantly ON (NOT FLASHING) if the transmission oil temperature is above 293°F (145°C). The "CHECK TRANS" light goes off again when the transmission oil temperature is below 257°F (125°C).