One of the most overlooked parts of car maintenance is keeping your gearbox oil fresh and filled. Especially if your vehicle is subject to high mileage or rough driving, it is essential that you change your gearbox oil. The more the clutch and transmission works, the more the oil is subject to "shear," losing its viscosity. Once you have drained out the old oil, you can fill gearbox oil in a few simple steps.
Locate the fill plug. This is typically on the top of the gearbox. If you are having problems locating it, follow the speedometer cable down to where it connects to the transmission; the fill plug will be near the cable.
Remove the fill plug.
Place a clean funnel in the fill hole and fill the gearbox with gear oil. Check your vehicle specifications to see how much is needed. Re-install the fill plug when done, hand-tighten and then torque the plug down with a socket wrench one turn.
