Just received my M816, Drove it around my place and found at some times seemingly in the right situation the drive line will seem to bind-up some and then let go with a big pop(sounds like a whack with a ball-pin hammer on a drive shaft. Have heard its due to the automatic frontwheel drive letting go. Seems like a tough sound, but I guess its a tough truck. I have not gone through the manuals enough to know how the system works, Me not knowing the system well makes me concerned something is not correct. I sure someone knows of this issue. thanks Mike.