When I pull up to a stop up light not always but most of the time I hear a knock it slowly gets louder unless you just push down on the four-wheel drive it shuts up instantly. Also it just started this it is a pain to get out of part or full its fowards backwards put it back into four-wheel and maybe it will come out. Plus it will not engage part time it wont move foward it just grinds unless you back up first.its Select a track system any ideas? I'm sorry if this is to much at once feel free to criticize. Thanks