My Aunt has a 2002 Honda Foreman 450es.
The breaks went out, so instead of changing breaks she started shifting down to slow down, and we checked the oil today and it didn't even read on the dipstick. Well the problem that occurred is it won't shift below 2nd.
And often when you shift up it doesn't read unless you push on it, and then the gear reads. We put a wrench on the shifter and shifted down, it moved enough to shift but for whatever reason it's not shifting.

We're wondering if riding without oil, they burned out the clutch or maybe some transmission problem, maybe a sensor.
And can someone point me towards a wiring diagram