MERCEDES-BENZ ML430 1997 Complete Repair Manual

Fig. 133: Shift From 1st To 2nd, Function (1st Gear Engaged)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

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Fig. 134: Shift From 1st To 2nd, Function (Shift Phase)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

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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Saturday, October 02, 2010 3:15:29 PMPage 234 © 2006 Mitchell Repair Information Company, LLC.

Fig. 135: Shift From 1st To 2nd, Function (Second Gear Engaged)
Courtesy of MERCEDES-BENZ OF NORTH AMERICA.
Aim
Engage front multiple-disc clutch (K1), disengage front multiple-disc brake (B1).
Operation
1st Gear Engaged
The end face of the 1-2/4-5 command valve (31a) is kept depressurized via the 1-2 and 4-5 shift solenoid valve
(Y3/6y3). Via the 1-2/4-5 holding pressure shift valve (28a), working pressure (p-A) is applied to the front
multiple-disc clutch (K1) is depressurized. See Fig. 133
.
Shift Phase
Via the 1-2 and 4-5 shift solenoid valve (Y3/6y3), the shift valve pressure (p-SV) is directed onto the end face
of the command valve 1-2/4-5 (31a). See Fig. 134
. The 1-2/4-5 command valve (31a) is displaced and the shift
pressure (p-S) coming from the 1-2/4-5 shift pressure shift valve (29a) via the 1-2/4-5 command valve (31a) is
directed to the front multiple-disc clutch (K1). At the same time the front multiple-disc brake (B1) is subjected
to overlap pressure from the 1-2/4-5 overlap regulating valve (30a).
The B1 pressure acting on the end face of the 1-2/4-5 shift pressure shift valve (29a) is superseded by the
working pressure (p-A). The increasing shift pressure (p-S) at the front multiple-disc clutch (K1) acts on the
annular area of the 1-2/4-5 overlap regulating valve (30a). With an appropriate pressure level at the 1-2/4-5
holding pressure shift valve (28a) this valve switches over.
2nd Gear Engaged
After the gear change is complete, the pressure on the end face of the 12-/4-5 command valve (31a) is reduced
via the 1-2 and 4-5 shift solenoid valve (Y3/6y3) and the command value is pushed back into its original
position. See Fig. 135. Via the 1-2/4-5 holding pressure shift valve (28a) working pressure (p-A) now reaches
the front multiple-disc clutch (K1) via the 1-2/4-5 command valve (31a).
The front multiple-disc brake (B1) is disengaged (depressurized). The spring in the 1-2/4-5 shift pressure shift
valve (29a) pushes this into its original position.
Operating Pressure, Function

See OPERATING PRESSURE, FUNCTION
.
Shift Pressure, Function

See SHIFT PRESSURE, FUNCTION
.
Modulating Pressure, Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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See MODULATING PRESSURE, FUNCTION
.
Shift Valve Pressure, Function

See SHIFT VALVE PRESSURE, FUNCTION
.
Lubricating Pressure, Function

See LUBRICATING PRESSURE, FUNCTION
.
Regulating Valve Pressure, Function

See REGULATING VALVE PRESSURE, FUNCTION
.
Limp-Home Mode, Function
Operation
In order to ensure a safe driving state and to prevent damage to the automatic transmission, the ECT control
module (N15/3) switches to limp-home mode in the event of critical faults. A fault code assigned to the fault is
stored in memory.
All solenoid and regulating valves are thus de-energized.
Effect
The gear last engaged remains engaged.
The modulating pressure and shift pressure rise to the maximum levels.
The torque converter lockup clutch is switched off.
In order to preserve the operability of the vehicle to some extent, the hydraulic control can be used to engage
2nd gear or reverse:
Stop Vehicle
Switch Off Engine
Move Selector Lever To "P"
Wait At Least 10 Seconds
Start Engine
Move Selector Lever To "D": 2Nd Gear
Move Selector Lever To "R"
The limp-home function remains active until the fault is rectified or the stored fault code is erased. Sporadic
faults can be reset via ignition OFF/ON.

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Upshift/Downshift Solenoid Valve, Location/Design/Task/Function

See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch

See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function

See MODULATING PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Shift Pressure Regulating Solenoid Valve, Location/Task/Design/Function

See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Operating Pressure, Function
The working pressure supplies pressure to the hydraulic control and transmission elements. The working
pressure is the highest hydraulic pressure in the entire hydraulic system. The working pressure is regulated at
the working pressure regulating valve in relation to the load and gear. All other pressures required for
transmission control are diverted from the working pressure.
Working Pressure Regulating Valve, Location/Task/Function

See WORKING PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function

See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Shift Pressure Control Solenoid Valve, Location/Task/Design/Function

See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Multiple-Disc Brake, Location/Task/Design/Function

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

See MULTI
-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Holding Pressure Shift Valve, Location/Task/Design/Function

See HOLDING PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Shift Pressure Shift Valve, Location/Task/Function

See SHIFT PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function

See OVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Location/Task/Function Of Command Valve

See LOCATION/TASK/FUNCTION OF COMMAND VALVE
.
Selector Valve, Location/Task

See SELECTOR VALVE, LOCATION/TASK
.
Location/Task/Design/Function Of Oil Pump

See LOCATION/TASK/DESIGN/FUNCTION OF OIL PUMP
.
Lubricating Pressure, Function
Operation
The working pressure regulating valve diverts surplus oil to the lubrication pressure regulating valve, from
where it is controlled and used for lubricating and cooling the mechanical transmission and torque converter. In
addition the pressure in the torque converter is limited via the lubrication pressure.
Working Pressure Regulating Valve, Location/Task/Function

See WORKING PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Lubrication Pressure Regulating Valve, Location/Task/Function

See LUBRICATION PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Torque Converter Lockup Clutch Regulating Valve, Location/Task/Function

See SHIFT PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function

See 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 3:15:29 PMPage 238 © 2006 Mitchell Repair Information Company, LLC.

Shift Pressure Control Solenoid Valve, Location/Task/Design/Function

See SHIFT PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Multiple-Disc Brake, Location/Task/Design/Function

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

See MULTI
-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.
Holding Pressure Shift Valve, Location/Task/Function

See HOLDING PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Shift Pressure Shift Valve, Location/Task/Function

See SHIFT PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function

See OVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Location/Task/Function Of Command Valve

See ELOCATION/TASK/FUNCTION OF COMMAND VALVE
.
Selector Valve, Location/Task

See SELECTOR VALVE, LOCATION/TASK
.
Location/Task/Design/Function Of Oil Pump

See LOCATION/TASK/DESIGN/FUNCTION OF OIL PUMP
.
Shift Pressure, Function
Operation
The shift pressure is determined by the shift pressure regulating solenoid valve (Y3/6y2) and the shift pressure
regulating valve.
The shift pressure:
Regulates the pressure in the activating shift element during the shift phase.
Determines together with the modulating pressure the pressure reduction at the deactivating shift element

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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as regulated by the overlap regulating valve.
Initializes 2nd gear in limp-home mode.
Shift Pressure Regulating Solenoid Valve, Location/Task/Design/Function

See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Shift Pressure Regulating Valve, Location/Task/Function

See SHIFT PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function

See OVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function

See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION
.
Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function

See MODULATING PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch

See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.
Multiple-Disc Brake, Location/Task/Design/Function

See NMULTIPLE
-DISC BRAKE, LOCATION/TASK/DESIGN/FUNCTION.
Multiplate Clutch, Location/Task/Design/Function

See MULTI
-PLATE CLUTCH, LOCATION/TASK/DESIGN/FUNCTION.
Holding Pressure Shift Valve, Location/Design/Function

See HOLDING PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Shift Pressure Shift Valve, Location/Design/Function

See SHIFT PRESSURE SHIFT VALVE, LOCATION/TASK/FUNCTION
.
Command Valve, Location/Design/Function

2001 Mercedes-Benz ML320
1998-03 AUTOMATIC TRANSMISSIONS Complete Transmissions - ML 320 - 722.662
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Saturday, October 02, 2010 3:15:29 PMPage 240 © 2006 Mitchell Repair Information Company, LLC.

See LOCATION/TASK/FUNCTION OF COMMAND VALVE
.
Selector Valve, Location/Task

See SELECTOR VALVE, LOCATION/TASK
.
Location/Task/Design/Function Of Oil Pump

See LOCATION/TASK/DESIGN/FUNCTION OF OIL PUMP
.
Modulating Pressure, Function
Operation
The modulating pressure influences the size of the working pressure and determines together with the shift
pressure the pressure regulated at the overlap regulating valve.
The modulating pressure is regulated at the modulating pressure regulating solenoid (Y3/6y1), which is under
regulating valve pressure. The modulating pressure via variable and relative to the engine load.
Modulating Pressure Regulating Solenoid Valve, Location/Task/Design/Function

See MODULATING PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Working Pressure Regulating Valve, Location/Task/Function

See WORKING PRESSURE REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Overlap Regulating Valve, Location/Task/Function

See NOVERLAP REGULATING VALVE, LOCATION/TASK/FUNCTION
.
Upshift/Downshift Solenoid Valve, Location/Task/Design/Function

See UPSHIFT/DOWNSHIFT SOLENOID VALVE, LOCATION/TASK/DESIGN/FUNCTION

Shift Pressure Control Solenoid Valve, Location/Task/Design/Function

See SHIFT PRESSURE REGULATING SOLENOID VALVE,
LOCATION/TASK/DESIGN/FUNCTION.
Location/Task/Design/Function Of PWM Solenoid Valve, Torque Converter Lockup Clutch

See LOCATION/TASK/DESIGN/FUNCTION OF PWM SOLENOID VALVE, TORQUE
CONVERTER LOCKUP CLUTCH.

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 241 © 2006 Mitchell Repair Information Company, LLC.