1. Gather the necessary materials. You will need:
* New gearbox oil (check your owner's manual for the correct type and quantity)
* A funnel
* A drain pan
* A wrench
* Safety glasses
2. Prepare your car. Park your car on a level surface. Turn off the engine and allow it to cool down. Engage the parking brake.
3. Locate the gearbox oil drain plug. The drain plug is located on the bottom of the gearbox. It is usually a 17mm bolt.
4. Place the drain pan under the drain plug. Make sure the pan is large enough to catch all of the oil that will drain out.
5. Loosen the drain plug. Use the wrench to loosen the drain plug. Be careful not to drop the bolt into the oil pan.
6. Allow the oil to drain. Allow all of the oil to drain out of the gearbox. This may take a few minutes.
7. Replace the drain plug. Once all of the oil has drained out, replace the drain plug. Tighten the plug until it is snug.
8. Locate the gearbox oil fill plug. The fill plug is located on the top of the gearbox. It is usually a 17mm bolt.
9. Remove the fill plug. Use the wrench to remove the fill plug.
10. Insert the funnel into the fill hole. Insert the funnel into the fill hole.
11. Add new gearbox oil. Add new gearbox oil to the gearbox. Add the amount of oil specified in your owner's manual.
12. Replace the fill plug. Once you have added the correct amount of oil, replace the fill plug. Tighten the plug until it is snug.
13. Check the gearbox oil level. Use the dipstick to check the gearbox oil level. The oil level should be between the "full" and "add" marks on the dipstick.
14. Start the engine and let it run for a few minutes. This will circulate the new gearbox oil throughout the gearbox.
15. Recheck the gearbox oil level. After the engine has been running for a few minutes, recheck the gearbox oil level. The oil level should still be between the "full" and "add" marks on the dipstick.
