Automatic Locking Differential - Mercedes-Benz 300 SL Operator's Manual

Automatic Locking Differential

(ASD)
The automatic locking differential
engages when there is a difference in
speed (slip) during acceleration
between the front and rear wheels of
over 1.2 mph (2 km/h) and the vehicle
speed is less than 15.6 mph (25 km/h).
It will disengage at speeds above 16.2
mph (26 km/h).
The yellow function indicator in the
speedometer comes on whenever there
is a difference in speed between the
front and rear wheels of over 1.2 mph
(2 km/h), warning of slippery road
conditions.
In steering lock position 2, the yellow
function indicator lamp and the yellow
ASD warning lamp in the instrument
cluster should come on and then must
go out with the engine running.
If the ASD warning lamp comes on
with the engine running, a malfunction
has been detected. We recommend that
you visit an authorized Mercedes-Benz
dealer as soon as possible to have the
ASD checked.
Caution!
If the vehicle is towed with the front
axle raised, the key must not be in
steering lock position 2. Otherwise, the
automatic locking differential control
will immediately be engaged, which
may cause loss of towing control.
Notes:
The automatic locking differential will
not engage at speeds above 15.5 mph
(25 km/h). However, above this speed,
a limited-slip effect of up to 35% is
always present.
When testing the parking brake on a
brake test dynamometer, turn off the
engine to avoid engaging the automatic
locking differential.
In winter operation, the maximum
efficiency of the automatic locking
differential can only be achieved with
Mercedes-Benz recommended M + S
radial-ply tires on all four wheels.
Acceleration Slip Control (ASR)
The acceleration slip control will
engage at all vehicle speeds, if one or
both drive wheels begin to lose traction
and spin due to
excessive acceleration. While engaged,
the yellow function indicator in the
speedometer lights up.
With the acceleration slip control
engaged, the brake is applied to the
spinning drive wheel until it regains
sufficient traction. If both drive wheels
lose traction and spin, the brake is
applied to both drive wheels and
simultaneously, engine torque is
limited.
As traction on the road surface
increases, the allowable engine torque
also increases again and the brake is no
longer applied to drive wheels.
Caution!
If the vehicle is towed with the front
axle raised, the key must not be in
steering lock position 2. Otherwise, the
acceleration slip control will
immediately be engaged and will apply
the rear wheel brakes.
Notes:
With the key in steering lock position
2, the yellow function indicator lamp
and the yellow ASR warning lamp in
the instrument cluster come on. They
must go out with the engine running
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