Chevy & GMC Vans

2001 AWD

When I start forward on drive pavement, which wheels are initially propelling the car forward--a single rear wheel? I have an ex Hertz rental van which I believe has a non-locking rear differential

The simple answer is that your rear wheels are driven first with little to no power being applied to the front wheels.

Yes in a non locking diff situation on slippery ground only one wheel will be being driven.

There are output shaft speed sensors in the transfer case that are determining speed of front and rear drive line... if the rear begins spinning faster than the front, say on a snowy road and pealing out the rear tires.... power will be applied to the front axle through a clutch pack in the transfer case and front and rear drive line speeds will match up.

Hope that helps.

Ryan