Figure 6.1. Plug for checking the oil level in the gearbox (shown by arrow) (bottom view):Left Gearbox F16; On the right is the F10 gearbox.
2. However, if for some reason the oil needs to be drained, this is done by removing the differential cover, which is made of pressed steel.
3. The plug for checking the oil level in the gearbox is located on the F16 gearboxes on the right side, next to the inner CV joint of the right drive shaft, and on the F10 gearboxes - on the left side (see figure 6.1).
4. The oil level should be at the bottom edge of the hole. If topping up is necessary, remove the ventilation plug from the gearbox housing and pour oil into the breather hole (see photo). Never pour oil into the hole to check its level.
(Material copied from this portal: OPELBOOK.ru)
Photo 2.4. Adding transmission oil to the box.
5. Use only the type of oil recommended for your transmission (see section "Recommended lubricants and working fluids" at the beginning of this Manual). It is prohibited to mix SAE 80 mineral oils with their semi-synthetic analogues. If you do not know what kind of oil is poured into the box, you should drain it completely and pour new oil into the box.

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