GMC 2001 Denali Owner's Manual page 307

Checking the Fluid Level
Prepare your vehicle as follows:
D
Park your vehicle on a level place. Keep the
engine running.
D
With the parking brake applied, place the shift lever
in PARK (P).
D
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 PARK (P).
D
Let the engine run at idle for three minutes or more.
Then, without shutting off the engine, follow these steps:
The red transmission dipstick handle is located at the
rear of the engine compartment, on the passenger's
side. See "Engine Compartment Overview" in the
Index for further location information.
1. Flip the handle up and then pull out the dipstick and
wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.
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