I just picked up a 2017 zForce 800 Trail and this is my first CFMoto.  Whenever I go for a ride I have gear oil leaking from the rear diff vent tube. 

I drained the rear diff and refilled with exactly 250ml of 80w90 gear oil (per the manual).  I put on a new vent tube, went for a ride and I am still getting fluid leaking.  I did a quick 6 mile loop with speeds constantly between 30 and 45mph.

I'm at a loss as to why this is happening.  I understand if the diff was overfilled or had water in it, but neither is the case.

What am I missing?  Do zForce just puke gear oil or what?  I something else wrong that I'm not thinking of? 

I'm starting to second guess my purchase.