Just picked um my first 4 wheeler , grew up on 3 wheelers and Moto bikes - paid 1700 for what seemed to be a great running Quad - the owner is a bike mechanic and seems to have a good on line presence etc ...
Within the first hour it staters making " clunking " sound in the front end , I am assuming the dig slipping ? Not a real grinding noise but clinking - happens under. Little bit of a up hill pull - or wheels turning --
I checked the fluid seems dry - not to cool in my book coming from a mech -

any thoughts , trouble shooting etc -

 

Put it up on jack stands and start turning the wheels by hand until you find where the noise is coming from.

And yes, not cool at all coming from a mech, any chance he will stand by his sale and look at it for you?