2003 Buick Century chang Transmission filter

The filter is inside the transmission pan. Remove the bolts around the edge holding the pan and pull it down. Unless your pan also has a drain hole (most U.S. Cars don't), you'll have to catch the fluid as is spills over the edges. Even with a big pan, it's a messy job.

The filter usually has a neck that presses into a hole. Make sure any old seal or o-ring around the neck is removed if it stuck in the hole and replace it with a new one. Clean the pan and the magnet inside it. Use the bolts to hold the gasket in place as you reattach the pan and torque them in stages evenly to specifications, usually around 12-15 foot pounds. The kits that come with a neoprene gasket require no sealant.