Differential oil/grease
 

From what I have read, there is a common issue with the differential fluid not being good enough, big surprise, and tends to leak from the rear end. I am wanting to add some to it but not sure what exactly to use. Any suggestions?

If you have a leak at the reduction box (behind the torque driver) you either have a failing seal(s), missing screw and/or cracked cover. Find the leak and fix it. As far as oil in there most scooters call for 80-90 Hypoid oil. I use Honda brand. On modded Zuma 2-strokes I use 10-30 synthetic motor oil.

The amount should be cast into the case, usually around 110cc.

Thanks I'll give it a look. I added some high temp grease yesterday. It took a good amount of pumps from the grease gun. We'll see how this works smh. The way this is going it might end up being cheaper to drive my diesel lol.

Using that grease is not recommended. I had a Honda Helix blow a seal on the reduction box wheel side, coating the rear wheel with oil. So to get home I packed the reduction box with axel grease. I got it home but it was nasty to clean up and i still had to replace all 3 bearings.