GMC 2012 Savana Owner's Manual page 263

Wait at least 30 minutes before
checking the transmission fluid level
if you have been driving:
When outside temperatures are
above 32°C (90°F).
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 82°C to 93°C
(180°F to 200°F).
Get the vehicle warmed up by
driving about 24 km (15 mi) when
outside temperatures are above
10°C (50°F). If it is colder than 10°C
(50°F), drive the vehicle in 3 (Third)
until the engine temperature gauge
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 10°C (50°F) or
more. If it is colder than 10°C
(50°F), the engine may have to idle
longer. Should the fluid level be low
during this cold check, the fluid must
be checked hot before adding fluid.
Checking the fluid hot will give a
more accurate reading of 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.
Then, without shutting off the
engine, follow these steps:
The transmission dipstick is located
near the center of the engine
compartment and will be labeled
with the graphic shown.
See
for more information.
1. Flip the handle up and then pull
out the dipstick and wipe it with
a clean rag or paper towel.