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TRANSFER CASE
7
TANSFER CASE
The lubrication oil flows through holes of the output
shaft which in turn lubricate the inner parts of
transfer case.
4.3.1.4 WORKING OF TRANSFER CASE
Transfer case is a two-speed, part-time electrical
shift transfer case.
The Transfer case system consists of:
1. Transfer Case with Shift Motor, Speed Sensor
and Electric Clutch.
2.
Electronic Control Unit
(ECU)
3. Mode selector switch on the Floor console and
Indicator lights 4H and 4L on the instrument
cluster
4. Harness to connect the above parts and power
input/output.
The power is received by input shaft which is
coupled with output shaft of transmission gear box
by matching splines. There are two outputs, one
for rear wheels and the other for front wheels.
Three selector positions are provided
.
Position
Speed Ratio
Operation
2H – Two high
position
1:1
Two rear
wheels are
driven at 1:1
speed ratio
4H – Four
high position
1:1
All four
wheels are
driven at 1:1
ration
4L – Four low
position
2.48:1
All four
wheels are
driven at
2.48:1 ratio
Planetary gear set provides gear reduction. Power
is transferred to the front wheel drive through a
chain drive.
Transfer case unit operates in an oil bath. An oil
pump is used to provide positive lubrication to the
planetary gear set and other upper output shaft
components
MODE OF SHIFTS
The different modes are obtained by rotating
selector switch for selection. This in turn gives
signal to the Electronic Control Unit (ECU), which
controls operations intelligently. It senses the
conditions and shifts the transfer case as per the
selected mode. Inbuilt diagnostic system is
provided in the Transfer case ECU for transfer
cases electrical components. The control over the
operations is obtained by using the Electronic
Control Unit
(ECU).
Different shift modes are;
2H – Two wheel high
4H – Four wheel high
4L – Four wheel low