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4ETS for Passenger Cars&

4ETS for W163

327 HO 06 4ETS (WJB,RP,GC) 02-27-04

Starting MY1998

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Objectives

At the end of this session, you should be able to:• Identify which 2004 models have the 4ETS option• List the advantages of 4ETS• List 4ETS mechanical components and describe their function• Explain basic operation of 4ETS• Describe transfer case maintenance procedures• Describe the unique features of the W163 transfer case• Explain the operation and function of the W163 system

These technical training materials are current as of the date noted on the materials, and may be revised or updated without notice. Always check for revised or updated information. To help avoid personal injury to you or others, and to avoid damage to the vehicle on which you are working, you must always ref er to the latest Mercedes -Benz Technical Publication and follow all pertinent instructions when testing, diagnosing or making repair.Illustrations and descriptions in this training reference are based on preliminary information and may not correspond to the final US version vehicles. Refer to the official introduction manual and WIS when available. Copyright Mercedes-Benz USA, LLC, 2004WIS document numbers shown apply to WIS Version USA/CDN at date of writing.Reproduction by any means or by any information storage and retrieval system or translation in whole or part is not permitted without written authorization from Mercedes -Benz USA, LLC or it's successors. Published by Mercedes -Benz USA, LLC Printed in U. S.A.

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ContentsMY2004 4ETS vehicles 4Purpose and advantages of 4ETS 6Driving with 4ETS 9Additional 4ETS components 104ETS Brake torque control range 194ETS block diagram 21MY2004 ETS Maintenance and service 22Model W163 25Off-roading with the W163 27W163 Transfer case and controls 29Transfer case control unit 32W163 block diagram 33W163 service notes 34

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MY2004 4ETS Vehicles

All ML-class vehiclesAll G-class vehicles

C-class sedans & wagons with V6 engine-NEW for 2004E-class sedans and wagons with V6 and V8 engines-NEW for 2004

S-class sedans with V8 engine-NEW for 2004 4

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AWD, 4WD, 4ETS and 4ETS+ • “AWD” and “4WD” are used interchangeably by some manufacturers• “Permanent” and “full-time” are sometimes interchanged, too• Here’s the way MB retail training literature puts it:

– C-, E-, S-class • System availability: Optional• Type of drive system: “4MATIC AWD with 4ETS”• Torque Split Front/Rear: Permanent 40/60 via center differential• 4ETS

– M-class, G-class• System availability: Standard• Type of drive system: "Permanent full-time 4WD”• Torque Split Front/Rear: G-class: 50/50 via center differential• Torque Split Front/Rear: M-class: 48/52 via center differential• G-class: 3 locking differentials. 4ETS with unlocked differentials• M-class: Low range 2-foot mode; downhill traction function. 4ETS+

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What is “4ETS”?

It is a system that:• is always in 4-wheel drive, without driver having to switch the

system “on”• works with ABS and ASR in the Electronic Stability Program

(ESP) to provide optimal handling stability and traction • distributes drive torque to the front and rear axle through a

transfer case, which acts like a center differential.• uses brake pressure to control wheel spin, transferring torque

to the wheel with traction• warns driver of wheel slip by flashing warning lamp in

instrument cluster

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Torque Application at the Wheels Having Traction

Wheels without traction are braked to transfer torque to the wheels with traction

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In Comparison to 1990-1993 “4MATIC”:

• Ride height lower• Simpler front suspension• No additional hydraulics• Less intrusive to interior space (floorpan)• More cost-effective• Reduced weight • Better fuel mileage• Improved turning radius• Tire life extended

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Driving With “4ETS”

• Nothing to switch “on”• Driver is informed via a flashing warning lamp in instrument

cluster that one or several wheels are starting to spin. (The owners manual says to ease off on the accelerator when this happens)

• Throttle reduction control (ESP) can be switched off using “ESP-OFF” button, but 4ETS continues to operate. Warning lamp stays illuminated in this mode.

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Additional 4ETS Components

• Transfer case• Propeller shaft, front• Front differential – mounted to engine oil pan on right side• Engine oil pan -• Front axle shafts – different length axles, but both ends identical

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Transfer Case

8 Hexagon nut with collar 9 Hexagon nut with collar10 Output flange to front axle 12 Output flange to rear axle 13 Output shaft to rear axle15 Transfer case rear cover16a Transfer case housing front16b Transfer case housing rear

17 Output shaft to front axle 18 Intermediate gear 19 Hollow gear 20 Input shaft 20a Securing washer 20b Washer 20c Securing washer 25 Planetary gear set

MY2004 components shown

Passenger Car

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Transfer Case Lubrication• Gears serve as an oil

pump-oil ducts and splasher pipe supply lube oil to bearings and planetary gear system

• Automatic Transmission Fluid (2004=001 989 2303)

• Lifetime fill

• For 2004: Check oil level at room temperature and

not at transfer case operating temperature.

Passenger Car

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Transfer Case Torque Distribution: MY1998-2002

3 = Double planetary gear set: acts as center differential

Passenger Car

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Transfer Case Torque Distribution: Starting MY2004

60 % of the drive torque is transmitted to the rear axle and 40 % to the front axle.

1. Output shaft rear axle.2. Double planetary gear

set

3. Spur gears4. Output shaft front

axle5. Input shaft

Passenger Car

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Friction Disc in 2004 Planetary Gear Set

• To help quickly transfer torque to the front wheels when the rear starts to spin. • It is critical that 4ETS receives accurate wheel speed signals in order to properly

control torque distribution. All 4 wheels / tires must have the exact same diameter and proper inflation pressures or the clutches will be damaged.

• A worn disc would be noticed when driving in very slick conditions and comparing response with that of a known good vehicle.

Passenger Car

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Transfer Case & Propeller Shafts

1. Propeller shaft to rear axle2. Double planetary gear set 3. Spur gears 4. Propeller shaft to front axle

The transfer case is directly flange-mounted to the automatic transmission.

MY2004 components

shown

Passenger Car

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Front Wheel Drive Components

1. Transfer case2. Propeller shaft to front axle gearbox3. Front axle gearbox4. Right front axle shaft5. Left front axle shaft

The driveshaft has been carried over from model 210 4MATIC and has been modified in length

MY2004 components shown

Passenger Car

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Front Axle Open Differential Cutaway

Front axle gear box on model 220 with engine 1131. Front axle gearbox mounted to oil pan2. Pinion gear3. Ring gear4. Engine Oil Pan with cast-in through pipe

MY2004 components

shown

Passenger Car

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4ETS Brake Torque Control Range

A. Control of rear axle• Engages upon slippage in range of 0 to 50mph• Once engaged, control may remain active up to 80mph

B. Control of front axle• Engages upon slippage in range of 0 to 25mph• Once engaged, control may remain active up to 50mph

Passenger Car

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4ETS Control LogicTraction control according to wheel speed• Low speeds: Individual brake application at any of the 4

wheels for maximum traction• Medium speeds: Limited brake pressure increase at the

2nd rear wheel if one rear wheel spins. Simultaneous pressure increase if both rear wheels spin. Stability and road adhesion take precedence.

• High speeds: Simultaneous braking pressure to both rear wheels if one spins. At the same time the system refrains from any braking intervention at the front axle to achieve the best possible handling stability.

Passenger Car

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4-ETS Block Diagram

FRT VSS

Terminal 61

Stop lamp switch

Data Link (X11/4)REAR VSS

Circuit 31

Power

N47/

Return pump Relay K40/

Hydraulic control unit A7/

Parking Brake

ETS warning lamp

ETS MIL

ABS MIL

Passenger Car

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Maintenance – MY2004 Transfer Case

Check oil level – port 7b

Filling with oil – port 7aThe rear transverse mount (45) and the drive shaft must be removed.

Draining oil – port 7cThe rear mount (45) and the right case mount (45a) must be removed.

7a Fill port7b Control port7c Drain port16 Transfer case45 Rear case mount45a Right case mount

Passenger Car

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Maintenance – MY2004 Front Differential

Check oil level – port 7Oil level should be at lower level of fill port.

Check oil level at room temperature - not at differential operating temperature.

Right wheel well

7 Fill port

Passenger Car

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Removing MY’04 Front Axle Shaft:

1 – extension or punch

2 – front axle shaft

Wrap chain tool around constant velocity joint and tighten. Tap against chain to remove axle.

Reference: WIS job AR33.30-P-0620P

Passenger Car

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Model W163 Starting MY1998

4ETS plus Hi/Low range

W163

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W163 vs. Passenger Cars

High/Low range motor Single speed rangeShift fork ------------

Chain drive Gear driveLubrication pump Splash lube

52%

48%

60%

40%

W163

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Off-Roading with the W163

• Possible to switch to Low range before driving off road, crossing water, or towing on steep grades.

• Low range of transfer case provides a 2.64:1 ratio (High range =1:1 ratio)

• Off-road software in ABS improves braking when in Low Range under 18.5mph. Front wheel brakes only allowed to partially lock. (Helps by packing dirt in front of tires. Steering may beaffected)

• Switching into either Low or High transfer case range can be done only if all of the conditions on next slide are met

W163

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High/Low Range Selection

Conditions:• Vehicle stopped• Selector in “N”• Idle (400-1500rpm)

High to Low – Lamp 2 flashes, then stays ON.

Low to High - 2 flashes, turns Off.

Conditions not met - flashes 5 times, turns off.

W163

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W163 Transfer Case & Controls

• High/Low range motor (A55)

• Control unit (N78)

• Low Range Switch (S97/6)

W163

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High/Low Range

Front gear set: selects High or Low range operation

Rear double planetary gear set (center differential): distributes torque to front and rear differentials

W163

LOWHIGH

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High Range Low Range

1 – Input shaft

2 – Intermediate shaft

11 – Reduction hub

13 – Shift fork

18 – Planetary gear set

19 – Planetary carrier assy

2.64:11:1

W163

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Transfer Case Control Unit (N78)

N78 retains DTCs while the ignition is on. All Activity Module (N10) stores the DTCs after ignition is switched off.

W163

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W163 Block Diagram

N78

Circuit 30

Circuit 15

Circuit 31

Transfer caseactuator motor

(A55)

Traction Control(N47/)

Transmission Controlmodule (N15/3

ME-SFI(N3/10)

“Low Range Lamp”A1e46

“Low Range Switch”(S97/6)

AAM (N10) X11/4

CAN-C

W163

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W163 Service Notes

• Transfer case is filled for life• ML transfer case must be in Hi range before disassembly • W163 transfer case has a total of 5 replaceable seals (items

#22, 24 at each output shaft, 37, 44 on exploded view drawing) • 3 seals can be replaced without removing transfer case (#24 at

rear, 37,44 on exploded view drawing)• Transfer case halves are sealed with silicone sealer only• Transfer case oil pump operates in forward gears only• Towing: MB recommends using flat bed equipment

– When towing with all wheels on ground, place gear selector in “N”, ignition switch in position “2”, at a speed of = 30mph and towing distance = 30 miles.

– See owners manual for more options/cautions

W163

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Transfer Case Exploded View

W163

Legend on next pages

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LegendW163

3Pinion spacer04j

90Needle brg04i

3Pinion gear04h

6Thrust washer04g

1Planet carrier04f

1Thrust washer04e

1Needle brg04d

1Input shaft04c

1Planet carrier plate

04b

3Pinion shaft04a

1Carrier compl.04

1Snap ring03

1Ball bearing02

1Snap ring01

QtyDescriptionItem No.

1Thrust washer09

1Oil pickup & filter

08g

2Hose clamp08f

1Hose08e

4Bolt08d

1Pump body08c

1Gear set08b

1Cover08a

1Gerotor pump08

1Bushing07b

1Int shaft07a

1Int.shaft compl07

1Reduction hub06

1Thrust washer05

QtyDescriptionItem No.

1Upper drive18a

1Upper sprcket18

1Spacer17

1Planet carrier16d

6Pinion gear16c

12Thrust washer16b

6Pinion shaft16a

1Carrier compl16

1Thrust washer15

1Rr output shaft14

1Diff ring gear13

1Retaining ring12

1Ball brg suppt11

1Ball brg10

QtyDescriptionItem No.

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LegendW163

1Lower drive sprocket

28

1Ball brg.27

1Magnet26

2Spring pin dwl.25

2Oil seal24

1Lwr output shft23

1Oil seal22

1Retaining ring21c

1Ring red. gear 21b

1Transfer case21a

1Case assy21

1Retng ring20

1Spacer19

1Bushing18b

QtyDescriptionItem No.

18Hex bolt34

1Shift rail33

1Elect shift cam 32d

1Torsion spring32c

1Spacer32b

1Shift shaft32a

1Shift shaft assy

32

1Shift fork pin31d

1Cam follower31c

1Shift fork red.31b

2Shift fork facg31a

1Red. Shft fork31

1Chain drive30

2Ball brg29

QtyDescriptionItem No.

ARRTV47

1ECU46

1Hex head screw

45

1Oil seal44

1Shift motor43

3Hex head bolt42

1Motor bracket41

2Drain plug40

1Stake nut39

1Washer38

1Oil seal37

1Companion flange

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1T-case cover35

QtyDescriptionItem No.