1997 MERCEDES-BENZ ML320 brake

Fig. 56: 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. See .Fig. 56
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
See Fig. 57
.
Sun Gear Locked
Ring Gear Driving
Planet Gears Driven
Relatively Low Step-Down Ratio

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Fig. 83: R/P-Lock, Function (Locking Position)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Function Of R/P Lock - The selector lever position "P" is locked whenever the R/P locking solenoid (89) is not
actuated by the electronic selector lever module control module (N15/5). See Fig. 83
. The prerequisites for this
are as follows:
No voltage supply to the electronic selector lever module control module (N15/5).
Brake pedal not depressed.
Under these conditions the locking lever (90) is in the locking position (P-lock).
The web on the locking lever (P-lock) (90b) locks the locking disc (69). It is not possible to shift the selector
lever (80) out of selector lever position "P".
Shift Detent Mechanism, Location/Task/Design/Function (Without Touch Shift)

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Shift Pressure Shift Valve, Function

See SHIFT PRESSURE SHIFT VALVE, FUNCTION
.
Shift Pressure Shift Valve, Function
Fig. 91: Shift Pressure Shift Valve, Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Operation - When the multiple-disc brake (B) is engaged, the working pressure (p-A) is applied to the end face
of the shift valve (29) via the command valve (31). See Fig. 91
. Its shift condition is retained in the shift phase,

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Fig. 106: Torque Converter Lockup Clutch, Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Operation
When actuated by the ETC control module (N15/3), oil pressure controlled by the torque converter lockup
PWM solenoid Valve (Y3/6y6) is directed through the input shaft (1) to the pressure chamber behind the piston
(16d). See Fig. 106
. The piston presses the clutch pack (16c) together and allows torque to be transferred
directly between the impeller (P) and turbine wheel (T). The torque converter lockup clutch is activated in 5th,
4th and 3rd gears in relation to the engine speed and engine load.
AUTOMATIC TRANSMISSION, FUNCTION
Transmission without touch shift. 722.6 in MODEL 163, 170, 202, 208, 210.
Transmission 722.6 in MODEL 129, 140.
Automatic transmission 722.6 is an electronically controlled 5-speed transmission with a lockup clutch in the
torque converter.
The ratios for the gear stages are achieved by three planetary gear sets. The 5th gear is designed with a step-up
ratio as an overdrive.
Shifting is initiated electronically. The gears are shifted by the corresponding combination of three
hydraulically actuated multi-plate brakes, three hydraulically actuated multi-disc clutches and two mechanical
freewheels.
Basically automatic transmission 722.6 with electronic control offers the following advantages:
Reduced fuel consumption
Improved shift comfort
More favorable gear steps as a result of 5 gears
Enhanced life and reliability
Reduced servicing costs
The electrohydraulic control unit is bolted onto the bottom of the transmission housing. The end of the
transmission is formed by an oil pan made of sheet steel.
The oil pressure for the converter lockup clutch and center multiple disc clutch is supplied via holes in the input
shaft. The oil pressure to the rear multiple-disc clutch is routed through the output shaft. The lubricating oil is
supplied and distributed by additional bore holes in both shafts. All bearing points of the gear sets as well as
freewheels and shift elements are supplied with lubricating oil.
The parking lock gear and drive flange are connected to the output shaft by gearing.
Freewheels F1 and F2 optimize shiftin
g. The front freewheel (F1) rests against the stator shaft extension on the

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:28 PMPage 183 © 2006 Mitchell Repair Information Company, LLC.

transmission side and connects the sun gear of the front planetary gear set to the transmission housing in the
locking direction.
The torque converter housing and transmission housing are made of a metal alloy. They are bolted together and
centered via the outer multiple-disc carrier of the multiple-disc brake B1. A coated intermediate panel seals the
two components.
The oil pump and outer multiple-disc carrier of the front multiple-disc brake are bolted to the converter housing.
The mechanical part consists of the propeller shaft, output shaft, a sun gear shaft and three planetary gearsets
which are coupled together.
In transmissions for powerful engines, the planetary gearsets have 4 planetary gears, while for less powerful
engines the front and rear planetary gear system has three planetary gear wheels. The stator shaft is pressed into
this and is secured against turning by a spline.
The rear freewheel (F2) connects the sun gear of the center planetary gear set to the sun gear of the rear
planetary gearset in the locking direction.
The electrohydraulic control unit consists of the shift plate made of light alloy for hydraulic control and an
electronic control unit.
The electrical control unit consists of a supporting body made of plastic in which the electrical components are
combined. The shell is screwed to the shift plate. Conductor tracks which are integrated into the shell, connect
the electric components to a plug connector. This 13-pin plug connector forms the connection with the vehicle-
side wiring harness and with the ETC 5 (electronic transmission control) control module (N15/5) via a bayonet
lock.
Automatic Transmission, Location Of Mechanical Components

See AUTOMATIC TRANSMISSION, LOCATION OF MECHANICAL PARTS
.
Automatic Transmission, Location Of Electrical/Electronic Components

See AUTOMATIC TRANSMISSION, LOCATION OF ELECTRIC/ELECTRONIC
COMPONENTS.
Automatic Transmission, Location Of Hydraulic Components

See AUTOMATIC TRANSMISSION, POSITION OF HYDRAULIC COMPONENTS
.
Automatic Transmission, Location of Components, Floor Shift

See AUTOMATIC TRANSMISSION, LOCATION OF COMPONENTS, FLOOR SHIFT
.
Automatic Transmission, Selector Lever Positions


2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Fig. 108: Selector Lever Positions
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
AUTOMATIC TRANSMISSION, FUNCTION
Transmission With Touch Shift 722.6 In Model 163
Transmission 722.6 is an electronically controlled 5-speed transmission with a lockup clutch in the torque
converter.
The ratios for the gear stages are achieved by 3 planetary gearsets. The 5th gear is designed as a low-rev gear
with an overdrive ratio.
Shifting is initiated electronically. The gears are shifted by the corresponding combination of 3 hydraulically
actuated multi-disk brakes, 3 hydraulically actuated multi-disk clutches and 2 mechanical freewheels.
The oil pump as well as the external plate carrier of the front multi-disk brake are bolted to the torque converter
housing.
The mechanical part of the transmission 722.6 consists of a drive shaft, output shaft, a sun gear shaft and 3
planetary sets which are coupled to each other.
The electrohydraulic control unit is screwed onto the transmission housing from below. The end of the
transmission if formed by an oil pan made of sheet steel.
The oil pressure of the torque converter lockup clutch and center multi-disk clutch is supplied via bore holes in
the drive shaft. The oil pressure to the rear multi-disk clutch is supplied via the output shaft. The lubricating oil
is supplied and distributed by additional bore holes in both shafts. Oil is supplied to all bearing points of the
gearsets as well as to the freewheels and shifting elements.
The parking lock gear and drive flange are connected to the output shaft by gearing.
Basically transmission 722.6 with electronic control offers the following advantages:
Reduced fuel consumption.
Greater ease of shifting.
Favorable spacing by 5 gears.
Long service life and high reliability.
Low maintenance costs.
The torque converter housing and transmission housing consist of a light-metal alloy. Both housings are bolted
together and are centered via the external plate carrier of the multi-disk brake at the front. A coated intermediate
panel seals the two components.
Freewheels F1 and F2 optimize shifting. The front freewheel F1 is supported on the extension of the stator shaft
on the transmission end and connects in the lockin
g direction the sun gear of the front planetary gearset with the

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Operation
The term power transmission refers to the transmission of propulsion power and engine torques. Via the
mechanical/hydraulic connection between the engine, torque converter and the downstream automatic
transmission the engine torques are transmitted to the driving wheels and are converted in the transmission via
several planetary gear sets.
Power is transferred in the torque converter via the driven impeller by diverting hydraulic fluid to the turbine
wheel, which is connected to the input shaft. See Fig. 117
.
When the torque converter lockup clutch is engaged, power is transmitted via this mechanical connection. Via
the gear wheels of the individual planetary gear sets the torques coming from the converter are passed on to the
output shaft with the aid of freewheels, multi-disk clutches and brakes, depending on the ratio and shift element
operated.
A reduction of the output speed in the low gears provides lower vehicle speeds with high tractive forces and
drive torques at the drive wheels.
Power Flow In 1st Gear, Function

See POWER FLOW IN 1ST GEAR, FUNCTION
.
Power Flow In 2nd Gear, Function

See POWER FLOW IN 2ND GEAR FUNCTION
.
Power Flow In 3rd Gear, Function

See POWER FLOW IN 3RD GEAR FUNCTION
.
Power Flow In 4th Gear, Function

See POWER FLOW IN 4TH GEAR FUNCTION
.
Power Flow In 5th Gear, Function

See POWER FLOW IN 5TH GEAR FUNCTION
.
Power Flow In Reverse, Function

See POWER FLOW IN REVERSE, FUNCTION
.
Function Of Torque Converter Lock-Up Clutch Control

See FUNCTION OF TORQUE CONVERTER LOCKUP CLUTCH CONTROL
.
Power Flow In 1st Gear, Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:28 PMPage 201 © 2006 Mitchell Repair Information Company, LLC.

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
.

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:28 PMPage 203 © 2006 Mitchell Repair Information Company, LLC.