Mercedes-Benz ML320. Manual — part 180

2001 Mercedes-Benz ML320

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

me

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 shifting. 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

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

See AUTOMATIC TRANSMISSION, SELECTOR LEVER POSITIONS.

Automatic Transmission, Gear Ratios

See AUTOMATIC TRANSMISSION, GEAR RATIOS.

Power Transmission, Function

See POWER TRANSMISSION, FUNCTION.

Gearshift System, Function

See FUNCTION OF GEAR SHIFT.

Hydropneumatic Transmission Control, Function

See HYDROPNEUMATIC TRANSMISSION CONTROL, FUNCTION.

Shift-Lock, Function

See SHIFT-LOCK FUNCTION.

Automatic Transmission, Location of Components, Floor Shift (Without Touch Shift)

2001 Mercedes-Benz ML320

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

me