well guys went to the track last night and went to do a burnout and the stage as soon as the green light turn on i hammered it and BOOOOOOM sounds like my differential went out, cuz all you hear at the diff is glunk glunk like crushed ice but here is the weird thing is that im in park and truck is off my truck still rolls forward while pushing and when truck is on and put into drive the driveshaft spins but truck dont move. so what do you all think it could be. you know when you change your rear tires one at a time and jack up one side first, well i can spin the tire freely all the way around without stopping, not like before it would only have a tiny bit of play.