clutch system SSANGYONG KORANDO 2013 User Guide

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This information is used by the TCU to decide which shift pattern to select and for shift energy
management. Electro-hydraulic solenoid valves and variable bleed solenoids control the transaxle gear
changes.
Six variable bleed solenoids and four on/off solenoids are used to direct transaxle fluid flow to control the
fluid pressure within the three clutches and two bands. Separate pressure regulators are used
exclusively for torque converter clutch control and main transaxle line pressure.
The TCU monitors all TCU inputs and outputs to confirm correct system operation. If a fault occurs the
TCU is able to perform default action and inform the driver of the problem through the instrument cluster
warning lights. Detailed information is available via trouble codes which can be read with the service tool.

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1. OVERVIEW
2WD4WD
The Model 6F24 6 speed automatic transaxle is electronically controlled. The control system is
comprised of the following components:
External transaxle control unit (TCU)
Input and output speed sensors
Six variable force solenoids(VFS) and two on/off solenoids
Torque converter
ATF temperature sensor -
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TCU controls the oil pressure for various internal clutches and brakes to select the gear. It also controls
the electronic elements, shift pressure and torque converter slip. If the system is defective, TCU provides
FMEC (Failure Mode Effect Control) to maintain the functionality of transaxle. This keeps the basic
function of transaxle (gear selection) even when there are failure in controls and power supply.
There are selector shaft position sensor (inhibitor switch) and oil temperature sensor in transaxle. In
manual mode, TCU receives the information from TGS (Transmission Gear Selector) through PCB
(Printed Circuit Board) when driver selects the manual shift mode. TCU communicates with other electric
control modules through CAN. In order to ensure a safe driving state and to prevent damage to the
automatic transmission, TCU switches to Limp-Home mode in the event of critical faults.

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2) Transaxle Cooling
The transaxle cooling system ensures rapid warm-up and constant operating temperature resulting in
reduced fuel consumption and refined shift quality.
It also includes a cooler by-pass within the hydraulic system to allow sufficient lubrication to the transaxle
drivetrain in the event of a blockage in the transaxle cooler.
3) Shift Strategy
Gear Change
Transaxle gear change is controlled by the
TCU. The TCU receives inputs from various
engine and vehicle sensors to select shift
schedules and to control the shift feel and
torque converter clutch (TCC) operation at each
gear change.
Coast down
Coast down down shifts occur at 0% pedal
when the vehicle is coasting down to a stop.
Torque Demand
Torque demand down shifts occur
(automatically) when the driver demand for
torque is greater than the engine can provide at
that gear ratio. If applied, the transaxle will
disengage the TCC to provide added
acceleration.

4. LIMP HOME MODE
When the transaxle is defective
In the event of a system fault, the TCU also provides for failure mode effect control (FMEC) to maintain
maximum functional operation of the transaxle. (There are 3 FMEC modes, mechanical limp-home
mode, electrical limp-home mode, limp-home mode C.)
In the event of a total loss of control or electrical power, the basic transaxle functions (Park, Reverse,
Neutral and Drive) are retained. The 4th and reverse gear ratios with the torque converter clutch in the
unlocked state are the retained gear states the hydraulic system supports without any electrical
assistance. (Mechanical limp-home)
If the speed sensor circuit is failed, the gear is fixed to 4th gear, but manual shifting
If the inhibitor switch signals are invalid, shifting to1st and 2nd gear is forbidden. (Limp-home C)
The TCU communicates with other vehicle electronic control modules by the controller area network
(CAN). If a major fault is developed, the transaxle may not accomplish the intelligent shift control. The
TCU controls the transaxle with preset values.
The TCU also provides for transaxle diagnostics, which meet the requirements of OBD II regulation,
monitoring all components which may effect vehicle emissions. 1.
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Towing the automatic transaxle equipped vehicle
Flat-bed equipment is the best method of moving a disabled vehicle to avoid any damages.
For AWD vehicle: The vehicle must be towed with a wheel lift and dollies or flatbed equipment with
all the wheels off the ground.
For 2WD vehicles: It is acceptable to tow the vehicle with the rear wheels on the ground without
dollies and the front wheels off the ground. When being towed by a commercial towtruck and
wheel dollies are not available, the front of the vehicle should be lifted, not the rear. -
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5. TRANSAXLE ELECTRONIC CONTROL SYSTEM
1) General Information
The transmission control unit (TCU) and its input/output network control the following transmission
operations:
Shift timing
Line pressure
Clutch pressure (shift feel)
Torque converter clutch -
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also uses these signals when determining transaxle operating strategy. Using all of these input signals,
the TCU can determine when the time and conditions are right for a shift, or when to apply or release the
torque converter clutch. It will also determine the pressure needed to optimise shift feel.
2) TCU (Transmission Control Unit)
The transaxle control unit (TCU) is mounted
under the driver's seat and controls the operation
of the transaxle.
Internal sensors and signals received across the
CAN bus in analogue and digital forms such as:
Transaxle input speed
Transaxle output speed
Accelerator pedal position
Gear selector position
Engine torque
Engine speed
Transaxle fluid temperature
Brake pedal status
Engine oil temperature
Engine coolant temperature
Ambient air temperature
Barometric pressure -
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The TCU monitors all TCU inputs and outputs to confirm correct system operation. If a fault occurs the
TCU is able to perform default action and inform the driver of the problem through the instrument cluster
warning lights. Detailed information is available via trouble codes which can be read with the service tool.

2. SATIC (SELF ADJUSTING TECHNOLOGY WITH
INTEGRATED CASSETTE)
Function
Operation
On the conventional clutch, the pedal force tends
to increase in proportion to the degree of disc
run-out. However, the SATIC clutch has the
adjusting function which activates the cassette
system inserted to the clutch cover to maintain a
constant pedal force and clearance when the
disc runs out. (Unlike SAT type, SATIC type
does not need SST for clutch cover removal.)
Diaphragm spring rotates the adjusting
equipment as clutch disc is wearing and so,
pressure plate is pushed to clutch disc side at the
amount of wear.
plate (4)
1) System Description

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Operating Elements
The clutch "release" system consists of the clutch pedal and clutch release cylinder.
This system directly releases the clutch by using hydraulic pressure while the conventional clutch system
releases the clutch by using release lever and release fork. This system provides higher efficiency than
conventional clutch system, and its durability is superior.
Clutch master cylinder (mounted on clutch pedal)
Concentric slave cylinder pipe (mounted inside of transmission) -
-Driving elements
The driving elements consist of two flat surfaces machined to a smooth finish.
One of these is the rear face of the engine flywheel and the other is the clutch pressure plate. The clutch
pressure plate is fitted into a clutch steel cover, which is bolted to the flywheel.
Driven elements
The driven element is the clutch disc with a splined hub which is free to slide lengthwise along the splines
of the input shaft.
The driving and driven elements are held in contact by spring pressure. This pressure is exerted by a
diaphragm spring in the clutch cover pressure plate assembly.
2) Overview

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2. SYSTEM LAYOUT
1) Components
(1) PTU (Power Transfer Unit)
and transfer it to E-coupling to distribute the torque to rear wheels.
(2) E-Coupling (Electronic Coupling)
E-Coupling transfer the engine torque from PTU to rear axle and controls to distribute it between front
wheels and rear wheels.
(3) E-Coupling Control Unit (ECU)
E-Coupling controls the current (clutch engagement force) of EMCD in E-Coupling according to CAN
signals (wheel speed, engine torque, pedal position, ABS/ESP signals).
* EMCD: Electro-Magnetic Control Device PTU assemblyE-coupling control unit
(located on the floor under driver seat)E-coupling