How can you add transmission fuel in your 2003 Buick Century?

You cannot add transmission fluid to a 2003 Buick Century (or most modern vehicles) yourself in the same way you add engine oil. The transmission uses a sealed system, and adding fluid incorrectly can cause serious damage. There's no readily accessible dipstick or filler neck.

If you suspect a problem with your transmission fluid (e.g., slipping gears, rough shifting, noises), you should take your Buick Century to a qualified mechanic or transmission specialist. They have the proper equipment and knowledge to diagnose the issue and, if necessary, perform a fluid and filter change or other repairs. Attempting to add transmission fluid yourself risks further damage to the transmission.