GMC 2000 Sierra - Manual (Page 323)

yellow blue
6-20
How to Check
Because this operation can be a little difficult, you
may choose to have this done at the 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.
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. 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:
D When outside temperatures are above 90_F (32_C).
D At high speed for quite a while.
D In heavy traffic
-- especially in hot weather.
D 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).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50
_F
(10
_C). If it’s colder than 50_F (10_C), drive the
vehicle in THIRD (3) until the engine temperature gage
moves and then remains steady for 10 minutes. Then
follow the hot check procedures.