Suzuki Wagon R Plus RB310, Service Manual

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AUTOMATIC TRANSAXLE (M13 ENGINE) 7B1-3
General 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 multi-
ple 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 (lock-up) solenoid valve and a timing solenoid valve. Optimum line pres-
sure complying with engine torque is produced by the pressure control solenoid valve in dependence upon con-
trol 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 con-
ducted.
– 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 shift-
ing.
– 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 compen-
sate 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 compen-
sate the line pressure every shifting.
Employing a 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.