Daewoo Korando. Manual - part 253

AUTOMATIC TRANSMISSION  5A-55

5A-56  AUTOMATIC TRANSMISSION

POWER FLOW - DRIVE 3 LOCK UP AND MANUAL 3 LOCK HP

In Drive 3 Lock Up and Manual 3 Lock Up, transmission drive is the same as for Drive 3 but with the application of the
converter lock up clutch to provide positive no-slip converter drive.

Control

Control for Drive 3 Lock Up and Manual 3 Lock Up is the same as for Drive 3 with the addition of the converter clutch
circuit activated by solenoid S7.

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When S7 is switched On, S7 feed oil to the converter clutch control valve is switched off and allowed to exhaust

through the S7 solenoid. This allows the valve to move to the clutch engage position.

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Regulated apply feed oil, derived from line 500 oil at the converter clutch regulator valve, is directed by the

converter clutch control valve to the engage side of the converter clutch.

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Converter clutch release oil is exhausted at the converter clutch control valve.

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Converter feed oil is re-routed by the converter clutch control valve directly to the oil cooler and lubrication

circuit.

Refer to figure 5.7and table 5.8.

Table 5.8 - Engaged Elements - Drive 3 Lock Up and Manual 3 Lock Up

Gear State

Drive 3 Lock Up and Manual 3

Lock Up

C1

X

C2

X

C3

-

C4

X

B1

-

B2

-

1-2

OWC

-

3-4

OWC

X

LU

CLUTCH

X

ELEMENTS ENGAGED

AUTOMATIC TRANSMISSION  5A-57

POWER FLOW - DRIVE 4 (OVERDRIVE)

In Drive 4 (Overdrive), transmission drive is via the input shaft to the forward clutch cylinder.

The elements of the transmission function as follows :

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The C1 clutch is applied to drive the planet carrier clockwise.

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The B1 band is applied to hold the reverse sun gear stationary.

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As the planet carrier tuns, the long pinion ‘walks’ around the stationary reverse sun gear and rotates around its

axis driving the internal ring gear and output shaft in a clockwise or forward direction at a speed faster than the
input shaft i.e. in overdrive ratio.

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The forward sun gear is also driven faster than the input shaft and overruns the 3-4 OWC.

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The C2 clutch is engaged to reduce the speed differential across the 3-4 OWC.

Control

To maintain this arrangement in the steady state solenoids and valves are activated as follows:

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Solenoid S1 is switched On. S2 is switched Off.

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With S1 switched On the 3-4 shift valve is held in the fourth gear position by line 500 pressure on the small end

of the valve.

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With S2 switched Off the 2-3 shift valve is held in the fourth gear position by line 500 pressure on the large
end of the valve.

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The 1-2 shift valve is held in the fourth gear position by S2 oil pressure.

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2nd oil (line pressure) from the 1-2 shift valve is directed to the band apply regulator valve, and to the 2-3 shift

valve.

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The band apply regulator valve supplies 2nd oil (regulated to line pressure multiplied by the valve ratio) to the

band apply feed (BAF) circuit.

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Band apply feed oil is directed to:

- the outer apply area of the front servo

- the inner apply area of the front servo piston via the 3-4 shift valve

- the 1-2 shift valve to provide an exhaust port when the transmission is shifted to first gear

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2nd oil at the 2-3 shift valve is directed to the 3rd oil circuit.

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3rd oil from the 2-3 shift valve is directed to the clutch apply regulator valve, and to the 4-3 Sequence Valve.

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The clutch apply regulator valve supplies oil (regulated to line 500 pressure multiplied by the valve ratio) to the

clutch apply feed (CAF) circuit.

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The CAF oil is directed to:

- the C1 clutch

- the C1 bias valve

- the 4-3 sequence valve

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Drive oil (line pressure) from the manual valve engages the C2 clutch

Refer to figure 5.8 and table 5.9.

Table 5.9 - Engaged Elements - Drive 4 (Overdrive)

Gear State

Drive 4 (Overdrive)

C1

X

C2

X

C3

-

C4

-

B1

X

B2

-

1-2

OWC

-

3-4

OWC

X

LU

CLUTCH

-

ELEMENTS ENGAGED

5A-58  AUTOMATIC TRANSMISSION