Transmission Fluid vs. Gear Oil?

[Jamez]

I've searched around on the forums here and have yet to find a thread that covers this. If I missed it, I apologize. It's time for me to replace my trans fluid / gear oil and I'm a little confused. Gear Oil is much thicker and Trans Fluid is much lighter. But which one do I use? It sounds like for Scooters, located towards the back that you insert Gear Oil and NOT Transmission Fluid. My owner's manual says otherwise? :o

Can someone explain this to me?