Pontiac 2004 Bonneville Owner's Manual page 300

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 is colder than 50°F (10°C), you may
have to drive longer.
Checking the Fluid Level
Prepare your vehicle as follows:
•
Park your vehicle on a level place. Keep the engine
running.
•
With the parking brake applied, place the shift lever
in PARK (P).
•
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).
•
Let the engine run at idle for three to five minutes.
5-24
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 5-14
for more information
on location.