How do you change the rear differential fluid on a 2003 Buick rendezvous?

To change the rear differential fluid on a 2003 Buick Rendezvous, start by raising the vehicle and securely supporting it on jack stands. Locate the rear differential housing, remove the fill plug first to ensure you can refill it later, then drain the old fluid by removing the drain plug. After the fluid has drained completely, replace the drain plug and refill the differential with the recommended fluid through the fill hole until it reaches the proper level. Finally, replace the fill plug and check for any leaks.