MERCEDES-BENZ ML430 1997 Complete Repair Manual

Fig. 118: Power Flow In 1st Gear, Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Principal of power transmission in 1st gear
The torque coming from the torque converter is increased and transmitted to the output shaft (5) via the input
shaft (1), involving all three planetary gear sets. See Fig. 118
.
The following are not engaged:
Front Multi-Disc Clutch (K1)

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Center Multi-Disc Clutch (K2)
Center Multi-Disc Brake (B3)
Front Planetary Gear Set
The input shaft (1) drives the internal gear (V4). In drive mode the sun gear (V1) is supported via the locked
freewheel F1 and in overrun mode via the engaged front multi-disc brake (B1) in the housing (B1). The
planetary gears (V2) roll over the fixed sun gear (V1) and provide an increase in torque between the internal
gear (V4) and the planet carrier (V3). The planet carrier (V3) moves at reduced speed in the direction of engine
rotation.
Rear Planetary Gear Set
The internal gear (H4) turns at a reduced speed because of its mechanical connection to the front planet carrier
(H3). The sun gear (H1) is supported via the engaged rear multi-disc brake (B2) and in drive mode via the
locked freewheel (F2), in overrun mode via the engaged rear multi-disc clutch (K3) in the housing. The planet
gears (H2) roll over the fixed sun gear (H1) and provide an increase in torque between the internal gear (H4)
and the planet carrier (H3). The planet carrier (H3) moves at a reduced speed in the direction of engine rotation.
Center Planetary Gear Set
The ring gear (M4) is driven at the same speed as the rear planet carrier (H3) as a result of a mechanical
connection. The sun gear (M1) is supported in the housing via the rear multi-disc brake (B2) (M1). The planet
gears (M2) roll over the fixed sun gear (M1) and provide an increase in torque between the internal gear (M4)
and the planet carrier (M3). The output shaft (5) connected to the planet carrier (M3) turns at a reduced speed in
the running direction of the engine.
Torque Converter, Location/Task/Design/Function

See TORQUE CONVERTER, LOCATION/TASK/DESIGN/FUNCTION
.
Planetary Gear Set, Location/Task/Design/Function

See PLANETARY GEAR SET, LOCATION/TASK/DESIGN/FUNCTION
.
Multiple-Disc Brake, Location/Task/Design/Function

See MULTIPLE
-DISC BRAKE, LOCATION/TASK/DESIGN/FUNCTION.
Multi-Plate Clutch, Location/Task/Design/Function

See MULTI
-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.
Location/Task/Design/Function Of Freewheel

See LOCATION/TASK/DESIGN/FUNCTION OF FREEWHEEL
.

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PLANETARY GEAR SET, LOCATION/TASK/DESIGN/FUNCTION
Fig. 119: Planetary Gear Set, Location/Task/Design/Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Planetary Gear Set, Location

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Three planetary gear sets are used to produce the different gear ratios. These are located in the mechanical
part of the transmission as the front, center and rear planetary gear set (V, M, H).
Planetary Gear Set, Task

Power transmission and production of different gear ratios.
Planetary Gear Set, Design

A planetary gear set consists of the ring gear (1), the planet gears (2) carried in the planet carrier (4) and
the sun gear (3).
Planetary Gear Set, Function

See PLANETARY GEAR SET, FUNCTION
.
Planetary Gear Set, Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Fig. 120: Planetary Gear Set, Function (1 Of 5)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Operation
The ring gear (1) and sun gear (3) elements of a planetary gear system are alternately driven and braked by the
actuating elements of the multi-plate clutch and multiple-disc brake. The planet gears (2) can turn on the
internal gearing of the ring gear (1) and on the external gearing of the sun gear (3). This allows for a variety of
gear ratios and the reversal of the rotation direction without the need for moving gear wheels or shift collars.
The torque and speed are converted corresponding to the lever ratios or the ratio of the number of teeth on the
driven to the driving gears and is known as the gear ratio i. The overall ratio of a number of planetary gear sets
connected in series is obtained by multiplying the partial ratios. When two components of the planetary gear set
are locked together, the planetary gear set is locked and turns as a closed unit.
Advantages Of A Planetary Gear Set:
Shifting ability under load.
Several ratios can be produced.
Constant meshing of the gears.
Simple direction reversal.
High efficiency.
Coaxial location of input and output.
Compact design.
The Following Basic Ratio Possibilities Can Be Realized
1.
Sun gear locked.
Ring gear driving.
Planet gears driven.
Relatively low step-down ratio.

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Fig. 121: Planetary Gear Set, Function (2 Of 5)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

2001 Mercedes-Benz ML320
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2.
Hollow gear locked.
Sun gear driving.
Planet gears driven.
Relatively high step-down ratio.

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Fig. 122: Planetary Gear Set, Function (3 Of 5)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
3. Locking two elements together so that the planetary gear set turns as a unit, produces a direct power

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transmission (i =1).
Fig. 123: Planetary Gear Set, Function (4 Of 5)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

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1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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