Mercedes-Benz 420 SEL 1988, Owner'S Manual

Page: 80 / 121

Fluid Level -
Automatic Transmission
Check the fluid level in the automatic
transmission regularly and prior to an
extended trip.
Check transmission fluid level with the
engine idling, parking brake engaged
and selector lever in position “ P” . The
vehicle must be parked on level
ground. Prior to the check, allow en­
gine to idle for approx. 1 to 2 minutes.
Measure fluid level with the dipstick
completely inserted and the locking
lever released (1).
Extreme cleanliness must be ob­
served! To wipe the dipstick, use a
clean, lint-free cloth. To fill the trans­
mission with fluid, pour it through a
fine-mesh filter into the dipstick open­
ing. Even the slightest impurity may
cause operational troubles.
The fluid level in the transmission is
dependent upon its temperature. The
maximum and minimum oil level
marks on the dipstick are applicable
references only if the transmission
fluid has reached its normal operating
temperature of 80° C (176°F).
Important!
If the transmission fluid cools down to
20-30° C (68-86° F), which is the nor­
mal shop temperature range, then the
maximum fluid level will be approxi­
mately 10 mm (0.4 in) below the
minimum mark on the dipstick. We
stress this point because a fluid
change is normally performed when
the transmission fluid has cooled
down to shop temperature.
The fluid level must not exceed the
dipstick maximum mark with the fluid
at operating temperature. Drain or
siphon off excess fluid, if required.
Then push dipstick all the way in and
swing locking lever downwards (2).
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