It's impossible to give a precise amount without knowing which transmission is in your specific vehicle. However, a general range for a drain and fill (which is less than a complete flush) is between 4-6 quarts. A complete flush might require significantly more fluid.
To find out the exact capacity for your Grand Prix:
1. Check your owner's manual: This is the best source of information. The manual should specify the transmission type and fluid capacity.
2. Look up your VIN: Use your vehicle's VIN number on a parts website or your local dealership to determine the exact transmission type installed. Once you know the transmission type (4T65-E or 5L40-E), you can search for the specific fluid capacity online.
3. Consult a repair manual: A repair manual for your specific year and model will give the precise fluid capacity for your transmission.
Do not attempt to overfill the transmission. Overfilling can cause damage. Always refer to your vehicle's specifications for the correct amount.
