Where do you put the transmission fluid in your 1998 Buick century?

The transmission fluid for a 1998 Buick Century is added through a dipstick tube located on the transmission itself. You'll need to consult your owner's manual for the exact location, as it's usually near the engine but can vary slightly depending on the specific transmission type (there might be variations even within the 1998 Century model year). The dipstick itself will likely be marked with "Transmission Fluid" or have a similar indicator.