At specified intervals, the transmission fluid should be drained and replaced, ensuring the engine has cooled down completely before starting. Purchase the appropriate transmission fluid along with a new filter and pan gasket. Necessary tools include a floor jack, jackstands for vehicle support, a drain pan with at least an eight-quart capacity, newspapers, and clean rags. Raise the vehicle securely on jackstands and place the drain pan underneath the transmission pan. If equipped with a drain plug, remove it to allow the fluid to drain, then reinsert the plug. For vehicles without a drain plug, remove all bolts except those in each corner, slowly taking out the front pan bolts to let fluid drain. Disconnect the shift linkage on the driver's side to access the pan bolts, then remove the transmission pan mounting bolts and carefully pry the pan loose. Clean the gasket surface of the transmission to remove old gasket and sealant, and clean the pan with solvent, drying it with compressed air if available. Some models have magnets in the transmission pan to catch metal debris, which should be cleaned thoroughly; a small amount of metal is normal, but significant debris may require consultation with a dealer or transmission specialist. Remove the filter from the valve body inside the transmission, taking care not to damage the aluminum gasket surface. Install a new seal and filter, ensuring the gasket surface on the transmission pan is clean before placing a new gasket on the pan. Position the pan against the transmission and install all bolts, tightening them gradually to the specified torque. Reinstall any components removed for access, lower the vehicle, and add approximately four quarts of the specified automatic transmission fluid through the filler tube. With the transmission in Park and the parking brake set, run the engine at a fast idle without racing it. Move the gear selector through each range and back to Park, then let the engine idle for a few minutes before checking the fluid level, adding more fluid as necessary to reach the proper mark on the dipstick while avoiding overfilling. Finally, check under the vehicle for leaks during the first few trips and verify the fluid level again when the transmission is hot.
