Mercedes-Benz 2007 CLS 550 User Manual download pdf (Page 5)

34 GEARS March 2009

Mercedes 722.9 Preliminary Information, Part 1

Range Sensor Function

The Y3/8s1 range sensor is

built into the ECM ribbon cable, and

can’t be replaced individually. It’s a

Permanent Magnetic Linear Contactless

Displacement (PLCD) sensor; it has a

permanent magnet mounted to the man-

ual valve, which changes the magnetic

field and output voltage as you move

the selector. If the sensor signal doesn’t

register properly with the computer,

it’ll put the system into limp mode.

Speed Sensor Function

The 722.9 uses three speed sen-

sors to monitor transmission operation

(figure 4):

1. The front speed sensor (Y3/8n1)

monitors turbine speed (input shaft

/ small ring gear).

2. The center speed sensor (Y3/8n2)

monitors the Ravigneaux carrier

speed (ring gear of rear planet).

3. The rear speed sensor (Y3/8n3)

monitors the park pawl gear (excit-

er ring/2 Hall Effect).

The magnets for these sensors are

molded in a plastic ring and secured

inside nonferrous flanges.

Transmission Fluid

Temperature

The transmission fluid temperature

sensor is built into the TCM, and isn’t

replaceable separately.

Clutch Components

The 722.9 uses four brakes and

three clutch packs to provide seven

forward gear ranges and two reverse

ranges.

• 4 Multi-Disc Brakes

• 3 Multi-Disc Clutches

• No Sprag

Gear ratios are achieved with one

Ravigneaux and two simple planetary

assemblies shown in figure 5. Unlike

the

Lepelletier geartrain, the 722.9

geartrain has the sun gear fixed to the

K1 clutch assembly, located in the front

of the unit (figure 6). The Ravigneaux

planetary assembly is also located in the

front section of the transmission (figure

7). There are two simple planets located

toward the back of the transmission,

one in front of the other (figure 8).

Fluid Type

The 722.9 uses a newly-developed,

suggested-use-only transmission fluid,

referred to as ATF 3353 (figure 9). It

promises a higher friction consistency,

thermal stability, and temperature rat-

ing. ATF 3353 can also be used on

previous model 722.3/.4/.5/.6 transmis-

sions. This special ATF is available

from Shell & Fuchs Europe oil sup-

pliers in 1 liter bottles under Mercedes

Benz part number A001 989 45 03 10.

No scheduled maintenance is

required for the 722.9 (fill for life).

In the next issue we’ll go into

sequential shifting, powerflow, and

some unusual features associated with

the Mercedes 722.9.

Figure 5

Unlike the Lepelletier

geartrain, the 722.9

geartrain has the

sun gear fixed to the

K1 clutch assembly,

located in the front of

the unit (figure 6).

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