GMC 2012 Savana Owner's Manual page 265

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 a small leak is
suspected, use the following
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 and
have it repaired before driving the
vehicle further.
Change the fluid and filter at the
intervals listed in
, and be
sure to use the transmission fluid
listed in
Because this operation can be
difficult, it is recommended to
have this check done at the dealer,
which can monitor the transmission
temperature. The transmission fluid
level increases with temperature. To
obtain a highly accurate fluid level
check, the transmission temperature
must be measured.
If it is decided to check the fluid
level, be sure to follow all the
instructions here, or a false reading
on the dipstick may occur.
.
Wait at least 30 minutes with the
engine Off, before checking the
transmission fluid level if the vehicle
has been driven:
In hot weather, when outside
temperatures are above
32°C (90°F).
The vehicle is heavily loaded.
At high speed for quite a while in
hot weather.
In heavy traffic and hot weather.
While pulling a trailer.
After driving under these conditions,
a hot check can be performed. The
fluid should be Hot, which is 71°C to
93°C (160°F to 200°F).
A cold fluid level check can be
performed 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 is between
15°C to 32°C (60°F to 90°F).