All Wheel Drive
Anybody notice any major differences or concerns with 4x4 towing vs All Wheel Drive towing? Considering a Denali with AWD and the 6 liter.
Forum Discussion
There seems to be a little confusion, most of the 1/2 ton in the market have a system that is BOTH quasi-AWD AND 4x4. My Expedition has this, and the Tahoe I test drove at the time was the same. It has 2WD, 4Auto, 4HI, 4LO. The transfer case is a 2 speed and locks the drive shafts together in 4HI and 4LO. Do not drive on pavement in either of these modes.
In 4Auto a variable clutch is used to allow slipping, it is designed to be driven on the street. 95% of the torque is still transfered to the rear. The computer measures the front and rear driveshaft rotations and if there is a difference the clutch begins to transfer more torque to the front. You can sometimes tell this is happening because on a low traction surface you may feel a slight bump and grab as rear starts to slip and torque is transferd forward.
The above system is not true AWD which divides the torque evenly all the time while still allowing slipage (think Subaru, I still miss mine :() I am not sure abou the most current Yukon Denali, but what I have read about the GMT-900 generation, the AWD left something to be desired. The Navigater AWD is just a 1 speed version of the above Control Trac system.
The Explorer 4x4 I had previous did not have 2WD option, only 4Auto 4HI 4LO. I towed my sig TT with it and never had any issues with it being in 4Auto. In fact, I loved it, and when towing will often select 4Auto on the Expedition. That way if I get into a limited traction situation I don't even have to think, it just works! For example, pulling onto a highway from the roadside fruit stand, there is no one wheel burnouts in the dirt trying to keep from getting run over, just point and press the go pedal. It has also saved my bacon on a patch of black ice.
In 4Auto a variable clutch is used to allow slipping, it is designed to be driven on the street. 95% of the torque is still transfered to the rear. The computer measures the front and rear driveshaft rotations and if there is a difference the clutch begins to transfer more torque to the front. You can sometimes tell this is happening because on a low traction surface you may feel a slight bump and grab as rear starts to slip and torque is transferd forward.
The above system is not true AWD which divides the torque evenly all the time while still allowing slipage (think Subaru, I still miss mine :() I am not sure abou the most current Yukon Denali, but what I have read about the GMT-900 generation, the AWD left something to be desired. The Navigater AWD is just a 1 speed version of the above Control Trac system.
The Explorer 4x4 I had previous did not have 2WD option, only 4Auto 4HI 4LO. I towed my sig TT with it and never had any issues with it being in 4Auto. In fact, I loved it, and when towing will often select 4Auto on the Expedition. That way if I get into a limited traction situation I don't even have to think, it just works! For example, pulling onto a highway from the roadside fruit stand, there is no one wheel burnouts in the dirt trying to keep from getting run over, just point and press the go pedal. It has also saved my bacon on a patch of black ice.
