General Description; A/T Description - Suzuki SX4 Service Manual

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A/T Description

This automatic transaxle is electronic control full automatic transaxle with forward 3-speed plus overdrive (O/D) and
reverse 1-speed.
The torque converter is a 3-element, 1-step and 2-phase type and is equipped with an automatically controlled lock-up
mechanism.
The gear change device consists of a ravigneau type planetary gear unit, 3 multiple disc type clutches, 3 multiple disc
type brakes and 2 one-way clutches.
The hydraulic pressure control device consists of a valve body assembly, pressure control solenoid valve (linear
solenoid), 2 shift solenoid valves, TCC solenoid valve (TCC pressure control solenoid valve) (linear solenoid) and a
timing solenoid valve. Optimum line pressure complying with engine torque is produced by the pressure control
solenoid valve in dependence upon control signal from transmission control module (TCM). This makes it possible to
control the line pressure with high accuracy in accordance with the engine power and running conditions to achieve
smooth shifting characteristics and high efficiency.
A clutch-to-clutch control system is provided for shifting between 3rd gear and 4th gear. This clutch-to-clutch control
system is made to function optimally, so that hydraulic pressure controls such as shown below are conducted.
• When upshifting from 3rd gear to 4th gear, to adjust the drain hydraulic pressure at releasing the forward clutch, a
timing solenoid valve is used to switch a hydraulic passage with an orifice to another during shifting.
• When downshifting from 4th gear to 3rd gear, to adjust the line pressure applied to the forward clutch at engaging
the forward clutch, a timing solenoid valve is used to switch a hydraulic passage with an orifice to another during
shifting.
• When upshifting from 3rd gear to 4th gear with engine throttle opened, to optimize the line pressure applied to the
forward clutch at releasing the forward clutch, the learning control is processed to compensate the switching timing
of the timing solenoid at every shifting.
• When downshifting from 4th gear to 3rd gear with engine throttle opened, to optimize the line pressure applied to
the forward clutch at engaging the forward clutch, the learning control is processed to compensate the line pressure
at every shifting.
Employing the ravigneau type planetary gear unit and this clutch-to-clutch control system greatly simplifies the
construction to make possible a lightweight and compact transaxle.
A line pressure learning control is conducted to provide optimum shifting time at every upshifting with engine throttle
opened. If long upshifting time is detected, the subsequent line pressure applied during upshifting is intensified. On the
contrary, if short upshifting time is detected, the subsequent line pressure applied during upshifting is weakened.

General Description

Automatic Transmission/Transaxle:
5A-3
S7RW0A5101001

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