Won't go into gear
 

05 800 after our ride yesterday -worked great all day- went to unload when we got home and could not get it to shift out of park. Used the winch to pull it off the trailer,so the ATV was running the whole time, after about 10 mininute of idleing it would shift. I left it in reverse over night and today it will not shift out of reverse. When it was stuck in park I thought it was the brake frozen not allowing it to shift but now I am lost with the reverse thing. Anyone have an idea what it could be. By the way we were riding in WI snow.

Won't go into gear
 

The shifter is frozen. The linkage going into the tranny (little black box) traps moisture and water but with the cold it will freeze and you wont get it to shift. You can let it sit and idle to thaw it out and then spray alot of wd40 or lubricant into where the shifter goes into the tranny.

Won't go into gear
 

i would change the rear gear drive fluid.