Pontiac 2005 Bonneville Owner's Manual page 287

Then, without shutting off the engine, follow these steps:
1. 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.
The transaxle fluid dipstick
top is a round, red loop
and is located next to the
brake master cylinder
behind the engine block.
See Engine Compartment
Overview on page 5-12
for more information
on location.
3. Check both sides of the dipstick, and read the
lower level. The fluid level must be in the
cross-hatched area.
4. If the fluid level is in the acceptable range,
push the dipstick back in all the way.
5-27