Note: A hex wrench or a suitable replacement will be required to loosen the drain and fill plugs (see text).
1. Place a suitable container under the gearbox drain plug at the bottom of the housing, then unscrew the plug. To make it easier to drain the oil, unscrew the filler / control plug located on the right side of the gearbox. To unscrew the plug, you will need a hex wrench, but if it is not available, you can use a tall nut or a piece of hex and a wrench (see fig. 2.1, a, b).
Pic. 2.1, a. Using a Tall Nut and Wrench to Loosen the Transmission Filler Plug
Pic. 2.1, b. Gearbox drain plug location
2. When all the oil has been drained, replace the plug with a new gasket.
3. Fill the gearbox with oil until the oil starts to flow out of the filler hole. The level should be at the bottom edge of the filler hole.
4. When the level is correct, install the plug and tighten it securely.