How To Check Automatic Transmission Fluid - GMC 2009 Yukon XL Owner's Manual

How to Check Automatic
Transmission Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer 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.
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.
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 should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).
5-22
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50°F
(10°C). If it is colder than 50°F (10°C), drive the vehicle
in 3 (Third) until the engine temperature gage moves
and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has been
sitting for eight hours or more with the engine off, but this
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 is colder than 50°F (10°C), you may have to
idle the engine longer. Should the fluid level be low during
this cold check, you must check the fluid hot before
adding fluid. Checking the fluid hot will give you a more
accurate reading of the fluid level.
Checking the Fluid Level
Prepare the vehicle as follows:
1. Park the vehicle on a level place. Keep the engine
running.
2. With the parking brake applied, place the shift lever
in P (Park).
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, position the shift
lever in P (Park).
4. Let the engine run at idle for three minutes or more.