GMC 2009 Sierra - Manual (Page 332)

Automatic Transmission Fluid
When to Check and Change
Automatic Transmission Fluid
It is usually not necessary to check the transmission fluid
level. The only reason for fluid loss is a transmission leak
or overheating the transmission. If you suspect a small
leak, then use the following checking procedures to check
the fluid level. However, if there is a large leak, then it
may be necessary to have the vehicle towed to a dealer/
retailer service department and have it repaired before
driving the vehicle further.
Notice: Use of the incorrect automatic transmission
fluid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission fluid listed in
Recommended Fluids and Lubricants on page 6-12.
Change the fluid and filter at the intervals listed in the
Maintenance Schedule. See Scheduled Maintenance on
page 6-4. Be sure to use the transmission fluid listed in
Recommended Fluids and Lubricants on page 6-12.
How to Check Automatic
Transmission Fluid
Notice: Too much or too little fluid can damage
your transmission. Too much can mean that some
of the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission fluid.
Before checking the fluid level, prepare your vehicle
as follows:
1. Start the engine and park your vehicle on a level
surface. Keep the engine running.
2. Apply the parking brake and place the shift lever
in PARK (P).
3. With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, move the
shift lever back to PARK (P).
4. Allow the engine to idle (500 – 800 rpm) for at least
one minute. Slowly release the brake pedal.
5. Keep the engine running and press the Trip/Fuel
button or trip odometer reset stem until TRANS
TEMP (Transmission Temperature) displays on
the Driver Information Center (DIC).
6. Using the TRANS TEMP reading, determine and
perform the appropriate check procedure. If the
TRANS TEMP reading is not within the required
temperature ranges, allow the vehicle to cool,
or operate the vehicle until the appropriate
transmission fluid temperature is reached.
5-20