Not familiar with a 1994 DT175 (I presume this is from the Asia (Far East) market).
The oil light will just be for the two stroke. There are no sensors that do gearbox, the most you get is a Neutral Light sensor (if you're lucky).
For the gearbox oil, the only sensors you see are with your eye balls and the oil sight glass.
I can't 100% say this is the case, but I say it with high confidence that this will be the case.
Hopefully that's useful.
Calum
