GMC Sierra Denali 2006, Owner'S Manual, Page: 301 / 438

Then, without shutting off the engine, follow these steps:
The transmission dipstick
handle is located at the
rear of the engine
compartment, on the
passenger’s side of the
vehicle.
See Engine Compartment Overview on page 5-10 for
further information on location.
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.
3. Check both sides of the dipstick, and read the lower
level. The fluid level must be in the COLD area,
below the cross-hatched area, for a cold check or in
the HOT or cross-hatched area for a hot check.
Be sure to keep the dipstick pointed down to get an
accurate reading.
4. If the fluid level is in the acceptable range, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
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