The NV136 transfer case is an automatic transfer case with two drive ranges. Shifting from rear wheel drive to four wheel drive is done automatically when the transfer case shift control module receives wheel rotating slip information from the speed sensors. The transfer case shift control module then engages the transfer case motor/encoder to position the transfer case from rear to four wheel drive. When the transfer case shift control module receives information that the wheel rotation is the same on both axles, the transfer case shift control module sends position information to the motor/encoder to put the transfer case back into rear wheel drive. The 2HI position is for normal driving with the rear wheels pushing the vehicle. The 4 wheel drive position is for driving through sand, snow, mud, gravel, or heavy rain at normal or slightly below normal speeds. The NV136 is manufactured at Syracuse New York by New Venture Gear a division of New Process Gear for General Motors.