7A1–4 AUTOMATIC TRANSMISSION (4L30-E)
GENERAL DESCRIPTION
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, then it sets the shifting point in
the optimum timing so that best driving perform-
ance can be achieved.
In addition, the built-in shift mode select function
can select two shift modes according to the driver’s
preference.
•
Normal mode –Normal shift pattern.
•
Power mode has a delayed upshift for when
more powerful acceleration is required.
Also, the built-in fail-safe function (”backup mode“)
assures driving performance even if the vehicle
speed sensor, throttle signal or any solenoid fails.
Further, the self-diagnostic function conducts
diagnosis in a short time when the control system
fails, thus improving serviceability.
The major features of 4L30-E are as follows:
•
A compact structure consisting of 2 sets of
planetary gears and flat torque converter.
•
Electronic control selects the optimum shift
mode according to the 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 of
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 perform-
ance.