Automatic Transmission Fluid - GMC 1999 Sierra 1500 Pickup Owner's Manual

Automatic Transmission Fluid
When to Check and Change:
A good time to check your automatic transmission fluid level is when the
engine oil is changed. Refer to the Maintenance Schedule to determine when
to change your fluid. See "Scheduled Maintenance Services" in the Index.
How to Check:
Because this operation can be a little difficult, you may choose to have this
done at a General Motors dealership Service Department.
If you do it yourself, be sure to follow all the instructions here, or you could
get a false reading on the dipstick.
I
Too much or too little fluid can damage your transmission.
Too much can
nean that some of the fluid could come out and fall on hot engine parts,
itarting a fire. Be sure to get an accurate reading if you check your
ransmission ftuid.
Wait at least 30 minutes before checking the transmission fluid level if you
have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic-especially in hot weather.
While pulling a trailer.
To get the right reading, the fluid must be at normal operating temperature,
which is 180°F to 200°F (82°C to 93°C).
To check the transmission fluid hot: Get the vehicle warmed up by driving
about 15 miles (24 km) when outside temperatures are above 50°F (1 0°C). If
it's colder than 50°F (lO°C), drive the vehicle in D (3rd gear) until the engine
temperature gage moves and then remains steady for ten minutes. Then
follow the hot check procedures.
To check transmission fluid cold: A cold check
is
made after the vehicle
has been sitting for eight hours or more with the engine
off and is used only
as a reference. Let the engine run at idle for five minutes if outside
temperatures are 50°F (10°C) or more. If it's colder than 50°F (lO"C), you
may have to idle the engine longer. A hot check must follow when fluid is
added during a cold check.
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