'Hinterachsantriebsöl '

My very humble excuses, but I do not know how to correctly translate 'Hinterachsantriebsöl' . Rear axle drive oil?

I have replaced 'all' fluids in my recently purchased SW, with the exception of the oil that is in the drive system of the rear wheel. [Page 3-16 in the German 'Werkstatt handbuch' (workplace manual)]

I have checked the level, and it seems it needs to be topped up, but I wonder how to do this without creating a mess, since it is a tiny hole, and quite deep to get to, as well. Does one use a seringe, or a tube???

On a German SW forum, I read about somebody who used a thicker grade oil (75W90) instead of the advised 10W40. He claimes to have a more silent drive since he used the ticker oil. Is this a good idea, or should I stick to 10W40?

Thanks in advance for your suggestions!

Stick to Hondas' recommendation.

I use a empty bottle of wood glew 300 mil. with a tapered pointy end, then I take a 1/8" aquarium air tub , stick it on the end of the screw cap 4" long .It fits into the screw hold,and there is no mess. It takes 250 mil. to fill it.

I used an pumping oil can:

I too use a pumping oil can... too easy.

75w90 gear oil is essentially the same viscosity as 10w40 motor oil - the viscosity of gear oil is measured differently than engine oil, so the 75w90 gear oil is not actually a thicker oil. It does have a different additive package however.

As for whether that additive package is better or not for the scooter, I don't know.

Gear oils generally have hi Sulphur content... you can smell it. It can adversley affect some brass/bronze bush material and therefor is not specified for some gearboxes. I would not use it if a motor oil is specified.