1997 MERCEDES-BENZ ML430 low oil pressure

Fig. 46: Multi-Disc Clutch, Function
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Operation
Front Multiple-Disc Clutch (K1) - If the piston (K1a) on the front multiple-disc clutch (k1) is subjected to oil
pressure, it presses the internal and external discs of the disc set together. See Fig. 46.
The front sun gear (V1) is connected to the front planetary gear carrier (V3) via the external multiple-disc
carrier (K1b) and the internal multiple-disc carrier (k1b) and the internal multiple-disc carrier (K1c). The front
planetary gear set is thus locked and turns as a closed unit.
Center Multiple-Disc Clutch (K2) - If the center multiple-disc clutch (K2) is engaged via the piston (K2a), the
piston compresses the disc set Via the internal multiple-disc carrier (K2b) and the center planetary gear carrier
(M3) on which the internal discs are seated, the front hollow gear (v4) of the front planetary gear set is
connected to the center hollow gear (M4) of the center planetary gear set. The front hollow gear (V4) and the
center hollow gear (M4) move at the same speed as the drive shaft (1).
Rear Multiple-Disc Clutch (K3) - If the rear multiple-disc clutch (K3) is engaged via the piston (K3a), then
this compresses the disc set. The center sun gear (M1) of the center planetary gear set is connected to the rear
sun gear (H1) of the rear planetary gear carrier via the external multiple-disc carrier (K3b) and internal multiple-
disc carrier (K3c). The center sun gear (M1) and the rear sun gear (H1) move at the same speed.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:26 PMPage 89 © 2006 Mitchell Repair Information Company, LLC.

lockup clutch (p-KUB) depending on the control pressure in converter lockup clutch (p-S/KUB). See Fig. 80.
Depending on the working pressure in the converter lockup clutch (p-KUB) the converter lockup clutch (KUB)
is:
Engaged
Disengaged
N slip mode
In the lower position of the converter lockup clutch regulating valve (27) lubricating oil (p-Sm) flows through
the torque converter and oil cooler (65) into the transmission (converter lockup clutch depressurized). In its
regulating position (slipping, torque converter lockup clutch pressurized), a reduced volume of lubricating oil
(p-Sm) flows through the annular passage (27a) bypassing the torque converter and passing direct through the
oil cooler (65) into the transmission. The other part of the lubricating oil (p-Sm) is led via the restrictor (a) into
the torque converter for cooling the converter lockup clutch (KUB).
R/P Lock, Location/Task/Design/Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Task - The ETC control module (N15/3) determines the instantaneous operating condition of the vehicle and
controls all gearshift sequences taking into account the ease of shifting and the driving situation. This involves
receiving, converting and transmitting various digital and analog signals. See Fig. 96
.
It receives operating data in the form of input signals from:
Starter Lock-Out Contact (Y3/6S1)
RPM Sensor 2 (Y3/6N2)
RPM Sensor 3 (Y3/6n3)
Transmission Oil Temperature Sensor (Y3/6B1)
In addition there is a connection via the engine compartment bus to the:
Instrument Cluster (A1)
ME-SFI Control Module (N3/10) or CDI Control Module (N3/9)
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):
Engine Torque
Engine Speed
Accelerator Pedal Position
Gear Shift
Engine Status
Electronic Selector Lever Module Control Module (N15/5):
Kickdown Switch (S16/6)
Selector Lever Position P/N
Traction System Control Module (N47):
Transmission Ratio
Speeds
Instrument Cluster (A1):
Selector Lever Position/Shift Range

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:27 PMPage 164 © 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
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Saturday, October 02, 2010 3:15:27 PMPage 166 © 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
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Saturday, October 02, 2010 3:15:28 PMPage 183 © 2006 Mitchell Repair Information Company, LLC.

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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Saturday, October 02, 2010 3:15:28 PMPage 189 © 2006 Mitchell Repair Information Company, LLC.

Task
The ETC control module (N15/3) determines the instantaneous operating condition of the vehicle and controls
all gearshift sequences taking into account the ease of shifting and the driving situation. This involves receiving,
converting and transmitting various digital and analog signals. See Fig. 157
.
It receives operating data in the form of input signals from:
Starter Lock-Out Contact (Y3/6S1)
RPM Sensor 2 (Y3/6N2)
RPM Sensor 3 (Y3/6N3)
Transmission Oil Temperature Sensor (Y3/6B1)
In addition there is a connection via the engine compartment bus to the:
Instrument Cluster (A1)
ME-SFI Control Module (N3/10) or CDI Control Module (N3/9)
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):
Engine Torque
Engine Speed
Accelerator Pedal Position
Gear Shift
Engine Status
Electronic selector lever module control module (N15/5):
Kickdown Switch (S16/6)
Selector Lever Position P/N
Traction system control module (N47):
Transmission Ratio
Speeds
Instrument cluster (A1):

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
me
Saturday, October 02, 2010 3:15:29 PMPage 277 © 2006 Mitchell Repair Information Company, LLC.

The ETC control module (N15/3) determines the instantaneous operating condition of the vehicle and controls
all gearshift sequences taking into account the ease of shifting and the driving situation. See Fig. 158
. 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)
Reverse And Parking Lock Solenoids (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
Gear Shift
Traction Status

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 280 © 2006 Mitchell Repair Information Company, LLC.