foreman gear jumping/shifting problem

I have an 05 foreman 500 es and yesterday i took it out and it jumps in 3rd. after i shift from 2 to the angle sensor makes a loud sound and it kinda jumps, like the chain is jumpin on a dirt bike. it only does it one time in that gear. (if i stayed in that gear all day it would only do it one time)

i should also mention is 25 degrees here and i had a lil problem when i went out and started it that morning. it flashed three times. i have already replaced the sensor this year so i wasn't too worried about it. so i let it warm up cuz i figured it was just frozen. and i was right. after it warmed up and i turned it off then back on it worked fine.

now this