4ETS for Passenger Cars
&
4ETS for W163
Starting MY1998
1
327 HO 06 4ETS (WJB,RP,GC) 02-27-04
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, 2004
WIS 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.
2
Contents
MY2004 4ETS vehicles
Purpose and advantages of 4ETS
Driving with 4ETS
Additional 4ETS components
4ETS Brake torque control range
4ETS block diagram
MY2004 ETS Maintenance and service
Model W163
Off-roading with the W163
W163 Transfer case and controls
Transfer case control unit
W163 block diagram
W163 service notes
4
6
9
10
19
21
22
25
27
29
32
33
34
3
MY2004 4ETS Vehicles
All ML-class vehicles
All G-class vehicles
C-class sedans & wagons with V6 engine-NEW for 2004
E-class sedans and wagons with V6 and V8 engines-NEW for 2004
S-class sedans with V8 engine-NEW for 2004
44
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+
5
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
6
Torque Application at the Wheels Having
Traction
Wheels without traction are braked to transfer
torque to the wheels with traction
7
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
8
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 “ESPOFF” button, but 4ETS continues to operate. Warning lamp
stays illuminated in this mode.
9
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
10
Passenger Car
Transfer Case
MY2004 components shown
8 Hexagon nut with collar
9 Hexagon nut with collar
10 Output flange to front axle
12 Output flange to rear axle
13 Output shaft to rear axle
15 Transfer case rear cover
16a Transfer case housing front
16b 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
11
Passenger Car
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.
12
Passenger Car
Transfer Case Torque Distribution:
MY1998-2002
3 = Double planetary gear set: acts as center differential
13
Passenger Car
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.
4.
5.
Spur gears
Output shaft front
axle
Input shaft
14
Passenger Car
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.
15
Passenger Car
Transfer Case & Propeller Shafts
MY2004
components
shown
1.
2.
3.
4.
Propeller shaft to rear axle
Double planetary gear set
Spur gears
Propeller shaft to front axle
The transfer case is
directly flange-mounted to
the automatic
transmission.
16
Passenger Car
Front Wheel Drive Components
MY2004 components
shown
1. Transfer case
2. Propeller shaft to front axle gearbox
3. Front axle gearbox
4. Right front axle shaft
5. Left front axle shaft
The driveshaft has been carried over from model 210
4MATIC and has been modified in length
17
Passenger Car
Front Axle Open Differential Cutaway
MY2004
components
shown
Front axle gear box on model 220 with engine 113
1. Front axle gearbox mounted to oil pan
2. Pinion gear
3. Ring gear
4. Engine Oil Pan with cast-in through pipe
18
Passenger Car
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
19
Passenger Car
4ETS Control Logic
Traction 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.
20
Passenger Car
4-ETS Block Diagram
Return pump Relay
K40/
Power
Circuit 31
Hydraulic control
unit A7/
Terminal 61
Stop lamp switch
ETS warning lamp
N47/
Parking Brake
FRT VSS
REAR VSS
ETS MIL
ABS MIL
Data Link (X11/4) 21
Passenger Car
Maintenance – MY2004 Transfer Case
Check oil level – port 7b
Filling with oil – port 7a
The rear transverse mount (45)
and the drive shaft must be
removed.
Draining oil – port 7c
The rear mount (45) and the
right case mount (45a) must be
removed.
7a
7b
7c
16
45
45a
Fill port
Control port
Drain port
Transfer case
Rear case mount
Right case mount
22
Passenger Car
Maintenance – MY2004 Front Differential
Check oil level – port 7
Oil 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
23
Passenger Car
Removing MY’04 Front Axle Shaft:
Wrap chain tool around
constant velocity joint
and tighten. Tap against
chain to remove axle.
1 – extension or punch
2 – front axle shaft
24
Reference: WIS job AR33.30-P-0620P
W163
Model W163
Starting MY1998
4ETS plus Hi/Low range
25
W163
W163
vs.
Passenger Cars
52%
60%
48%
40%
High/Low range motor
Shift fork
Single speed range
------------
Chain drive
Lubrication pump
Gear drive
Splash lube
26
W163
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 be
affected)
• Switching into either Low or High transfer case range can be
done only if all of the conditions on next slide are met
27
High to Low – Lamp
2 flashes, then stays ON.
Low to High - 2 flashes, turns Off.
Conditions not met - flashes 5 times,
28
turns off.
W163
W163 Transfer Case & Controls
• High/Low range motor
(A55)
• Control unit (N78)
• Low Range Switch
(S97/6)
29
W163
High/Low Range
HIGH
LOW
Front gear set: selects High or Low range operation
Rear double planetary gear set (center differential): distributes torque to front
and rear differentials
N78 retains DTCs while the ignition is on. All Activity
Module (N10) stores the DTCs after ignition is switched off.
32
W163
W163 Block Diagram
CAN-C
Circuit 30
Circuit 15
Transmission Control
module (N15/3
Circuit 31
“Low Range Switch”
(S97/6)
Transfer case
actuator motor
(A55)
Traction Control
(N47/)
N78
ME-SFI
(N3/10)
AAM (N10)
X11/4
“Low Range Lamp”
A1e46
33
W163
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