Like many General Motors vehicles, a 2005 Chevy Malibu has a sealed transmission with no dipstick, so you can't check the transmission fluid level without getting underneath the car and looking at the transmission itself.
The Malibu transmission has two plugs; one on the top that is used to add transmission fluid, and one on the side that is used to check the fluid level. When fluid runs out of the open plug on the side, the transmission fluid level is high enough.
Raise the vehicle high enough that you can get underneath. Support it securely with an automotive lift or jack stands.
Locate the transmission. Look for a small plug with a hex bolt on the passenger side of the transmission, adjacent to the passenger side front tire. The plug is slightly below and in front of the transmission's half shaft. Place a pan under this plug to catch any transmission fluid that may come out.
Start the engine and let it warm up to regular operating temperature. Shift through each gear in turn, waiting three seconds between each shift. Leave the engine running.
Remove the hex bolt from the plug hole in the side of the transmission with a wrench or socket. If transmission fluid flows freely from the hole, the fluid level is correct. If it barely drips, or no fluid comes out, the transmission fluid level is low.
Inspect the conical washer on the hex bolt from the plug hole and replace it if necessary. Replace the hex bolt in the plug hole and tighten it. Turn off the engine and lower the car.
Dispose of transmission fluid properly. In many areas, transmission fluid can be recycled.
Support the vehicle safely when working underneath it. A falling car can cause serious injury or death.