Vent line spew need help

Iv got a 2013 rzr 800s with a tuner 30in tires and a snorkel kit it has 280 hrs and 2000 miles we were driving 14-16 miles up a mountain and on top in high range and my ole lady said she heard a noise about 2 miles till we stoped and the vent line spewed oil out quite a bit it runs down to the trans i think i can see it when looking from the rear end behind a electrical plug and when i checked the fluid it was probably 3/4 in below the fill line what is wrong ?????????