Unscrew the drain plug with a hex wrench «at 12», drain the used oil. Then we wrap the cork in place, cleaning its magnet from steel chips.
Fill the oil through the hole closed with a plug, in the back of the beam, unscrewing it with a key «at 17».
If the oil drained from the gearbox housing is dark in color or metal particles are visible in it, it is necessary to flush the gearbox. To do this, fill it with about 1 liter of a mixture of gear oil with 20–30% kerosene or diesel fuel. Then, having hung one of the rear wheels, we turn on the 1st gear and start the engine. After 2-3 minutes, drain the flushing mixture and pour 1.3 liters of gear oil into the gearbox.
The oil level should reach the lower edge of the filler hole.