1997 MERCEDES-BENZ ML320 wheel torque

vehicle is stationary and the engine is idling, boosts the engine torque and provides infinitely variable
engine speed and torque matching when moving off.
Torque Converter, Design

The impeller (P) is connected to the engine, the turbine wheel (T) is connected to the transmission input
shaft.
The stator (L) is connected to the transmission housing via a freewheel and the stator shaft (8).
Torque Converter, Function

See TORQUE CONVERTER, FUNCTION
.
Torque Converter, Function
Due to the effect of centrifugal force, the blades of the impeller (P) pump the oil outwards to the turbine wheel
(T), causing it to rotate. See Fig. 31
. The turbine wheel blades direct the oil onto the blades of the stator, which
in turn push the oil back to the impeller (P) (arrow). This diversion at the stator (L), which is supported against
the transmission housing via the freewheel, produces and increase in torque. At the maximum speed difference
between the impeller and the turbine wheel (T), the torque conversion achieves its maximum value at a factor of
1.8 to 2.0, dropping to a torque ratio of 1:1 as the speeds converge. From this operating state onwards, also
referred to as the coupling point, the stator (l) rotates with the impeller (P) and the turbine wheel (T).
Efficiencies of up to approximately 98% are achieved in the coupling range.
The oil in the torque converter is constantly being replaced so that the heat produced in the operating phase can
be dissipated via the transmission oil cooler.

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:26 PMPage 63 © 2006 Mitchell Repair Information Company, LLC.

Fig. 31: Torque Converter, Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Wheel Speed Sensor, Location/Task/Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:26 PMPage 65 © 2006 Mitchell Repair Information Company, LLC.

In the front planetary gear set a freewheel (F1, F2) is installed between the front sun gear (V1) and the
stator shaft (8) and in the rear planetary gearset between the rear sun gear (H1) and the intermediate shaft
(3). See Fig. 37
.
Freewheel Task

Optimizes individual gearshifts. Support of the individual elements of a planetary gear set against each
other or against the transmission housing in one direction of rotation in order to permit torque
transmission.
Freewheel Design

The freewheels (F1, F2) consist of an outer race (12), an inner race (13), a number of clamping bodies
(14) and a clamping body cage (15).
Freewheel Function

See FREEWHEEL, FUNCTION
.
Freewheel, Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:26 PMPage 75 © 2006 Mitchell Repair Information Company, LLC.

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
me
Saturday, October 02, 2010 3:15:26 PMPage 103 © 2006 Mitchell Repair Information Company, LLC.

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Task - The ETC control module (N15/3) determines the instantaneous operating condition for the vehicle and
controls all gearshift sequences taking into account the ease of shifting and the driving situation. See Fig. 97
.
This involves receiving , converting and transmitting various digital and analog signals.
Input signals:
Starter Lock-Out Contact (Y3/6S1)
RPM Sensor 2 (Y3/6N2)
RPM Sensor 3 (Y3/6N3)
Transmission Oil Temperature Sensor (Y3/6B1)
Kickdown Switch (S16/6)
Gear Recognition Switch (S16/10)
Output signals:
Reverse/parking lock valve
Input and output signals:
Datalink connector (X11/4)
In addition there is a connection via the engine compartment bus to the:
ME-SFI Control Module (N3/10) or CDI Control Module (N3/9)
Traction System Control Module (N47)
Transfer Case Control Module (N78)
The solenoid valves for the modulating and shift pressure and for the gear changes are actuated by the ETC
control module (N15/3). The pressure required is calculated from all input signals, adjusted to the torque to be
transferred.
The following information from other systems is then processed:
ME-SFI Control Module (N3/10) or CDI Control Module (N3/9)
(Y66/1)
Selector lever position P/N to the engine control module (ME-SFI) (N3/10) (only on detection of the
selector lever position "P" or "N" on the transmission range recognition switch (S16/10) and at the starter
interlock contact (Y3/6s1)).
Traction system control module (N47):
Wheel speeds

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:27 PMPage 166 © 2006 Mitchell Repair Information Company, LLC.

The external plate carrier (16a) is connected to the impeller (P) via the cover shell (17). The internal plate
carrier (16b) is connected to the turbine wheel (T).
Torque Converter Lockup Clutch, Function

See Torque Converter Lockup Clutch, Function
. See TORQUE CONVERTER LOCKUP
CLUTCH, FUNCTION.
Torque Converter Lockup Clutch, Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:28 PMPage 181 © 2006 Mitchell Repair Information Company, LLC.

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
me
Saturday, October 02, 2010 3:15:28 PMPage 184 © 2006 Mitchell Repair Information Company, LLC.