Can someone explain to me how the AWD system works?
The reason is I was checking out the underside of my Aviator for winter damage during my annual spring cleanup. I saw the drive shaft to the front diffy from the transfer case and noticed a part number sticker on the shaft.
When I looked again later after driving it, I noticed the shaft had been turning, that sticker was in a different spot. The roads are dry, I hadn't done any slipping.
My AWD is in auto all the time, does it put power to the front wheels all the time? Do all four wheels get power, or just one wheel on each axle, like an open differential would do?
What does it mean when I can push a button on the dash and go from auto to locked? What am I locking?
I assume it would be the same as AWD on Explorers and Mountaineers.
I have had a 4x4 truck before, a 1990 Bronco. But it's 4x4 system disconnected the whole front driveline when it was off. It had a push button that activated the 4x4 by putting power to the front wheels where the auto hubs locked in. When you shut it off, I just pushed the button and backed up about 10 feet to unlock the hubs. The Aviator AWD system seems to be a completely different animal.
Also, I'm starting to get a little gear noise/whine at low speeds, but the dealer checked and say nothing is wrong. Would a change of lubes be in order? What do the front and rear diffys and T-case use? Would it stop the noise?
Thanks for your help.

 

not sure exactly what year you got. i can tell you we have a 2002 EXP and the buttons are AUTO, 4x4 low and 4x4 hi. When it AUTO, the computer is monitoring how fast the back tires are rotating compared to the front. if there is a big difference (lets say 20%), then the front end is engaged and starts to pull. It may be rotating as you drive down the road, but not powered. Some engage the drive shaft at the transfer case, some years engage the axle half shafts at the pumpkin. Gear whine is not abnormal in the 2002 model years and there about. You should use 75w 140 synthetic gear lube in teh back axle and regular 80-90 in the front. THe transfer case uses MERCON V same as the transmission. Does the noise frequency increase as speed increases? Wheel bearings are known to go bad also.

 

You have full time automatic AWD. Your center diff is limited slip or so it says:

2003 Lincoln Aviator 4 Dr STD AWD SUV - Overview for used Lincoln Aviator - CarGurus

I couldn't find a better write up, but would suggest you get an owner's manual if you don't have one already. Double check the lube type, especially for the transfer case.

My '98 Exploder has automatic 4wd, with selectable 4 hi and 4 lo. It works differently than you present or your older system. Mine will kick in automatically with far less than 20% wheel slip--probably 2%, but while it is not an abrupt or harsh engagement, you can feel it. I doubt you can feel yours "kick in", as it's being feed torque all the time via the center diff just like the R and L wheels get fed torque via the differential in the axle.

I'm sure there is a more technical write up of the system, but several years after intro, it's hard to find on the net.