Transmission Filter Removal

• 1). Raise your Buick Century with a jack and support it on jack stands.
  
  
• 2). Remove the pan bolts from the front and side of the trans-axle fluid pan with a box wrench. Do not confuse the trans-axle fluid pan with the engine oil pan. Loosen the rear bolts a few turns but leave them threaded in place.
  
  
• 3). Use a flat head screwdriver to gently pry the pan loose from the trans-axle and let the fluid drain into a catch pan.
  
  
• 4). Remove the rear bolts, pan and gasket. Discard the old gasket. Clean out the pan with a solvent, checking for large metal shards or other foreign objects. It is normal to have some fine metal material in the pan, but larger objects could indicate more serious problems in the trans-axle. Make sure the pan is completely dry.
  
  
• 5). Remove the filter and O-ring.
  
  

Transmission Filter Installation

• 1). Install the new filter and O-ring in place. The filter should be touching the dipstick stop. Install the new gasket onto the pan.
  
  
• 2). Tighten the bolts to 8 foot-pounds with a torque wrench.
  
  
• 3). Lower the vehicle off the jack stands with the jack and add 4 quarts of transmission fluid. Start the engine, block the wheels and set the parking brake. Shift the transmission through all of its gears, then put it in park and check the fluid level with the engine idling. Add more fluid if necessary.