Unimog Club UK

Welcome stupot
Your gearbox wants non hypoid 80 and your axles ep 80/90 gear oil and if your carrying a lot of weight I would recommend sintranz from MB it is debatable if it's worth the cost if your not working your Unimog the other advantage is it frees up some power when it's cold, you can get synthetic oil for the gearbox to but again it costs a lot in comparison.
There are two drains on the gearbox one fill, early gearbox, fill it through the dipstick and later one has a level plug on the right side.
Check levels before dropping any oils that way if it's over full you know you've got a seal gone up line also give the hubs a flush through and look for any metal.
Enjoy
Moose