Any reason not to drive with auto 4wd on full time?

[ExpeditionAndy]

I drive around in 2H most of the time and go to 4A when its wet or slippery outside. I only use 4H when I'm in deep snow, and have only used 4L on very rare occasions when I need the torque at low speeds. That's my nickle's worth.

 

[mossback]

I drive around in 2H most of the time and go to 4A when its wet or slippery outside. I only use 4H when I'm in deep snow, and have only used 4L on very rare occasions when I need the torque at low speeds. That's my nickle's worth.

Ditto.

 

[JExpedition07]

I drive around in 2H most of the time and go to 4A when its wet or slippery outside. I only use 4H when I'm in deep snow, and have only used 4L on very rare occasions when I need the torque at low speeds. That's my nickle's worth.

A shiny new nickel at that

 

[Boose]

I know enough to be dangerous, no expert ... barely head above water on this and many other topics.

BUT there is a WIKI page on this ...
https://en.wikipedia.org/wiki/ControlTrac#The_Modes

and this quote from the WIKI says the opposite
of what you typed about 4Auto above?
So I disagree. if I'm wrong , forgive me ...

Auto mode was featured on both Explorer and Expedition and allows for all-weather, full-time four-wheel drive capability on pavement as needed. In Auto mode, the engine’s torque is normally routed to the rear drive wheels. A misconception about the system is that it continuously shifts into and out of four-wheel drive as needed. This is not true, for when Auto mode is selected, the front axle hubs are permanently engaged, locking them to the front axle shafts, front differential, and front drive shaft. This is so the front drive shaft always rotates (turns) when the vehicle is being driven at speed. The computer control system needs the front drive shaft to turn, so that it can monitor and compare the rotational speed of both the front and rear drive shafts. If the rear drive shaft starts to turn faster than the front, the system interprets that (along with input from other sensors) as traction loss. When traction loss is detected, torque is sent forward to the front differential in 10 percent increments, via the center multi-disc clutch. As it does so, intelligent control software allows the center multi-disc clutch to behave like a geared center differential, such that "driveline binding" and "torque windup" do not occur. The transfer of torque is done in secrecy, virtually undetectable by the occupants of the vehicle.

In the early 2000s, ControlTrac was updated and introduced in 2002 with more advanced software programming, building on the system’s artificial intelligence.[8] The four-wheel drive system's updated artificial intelligence allowed the system to predict traction loss before it happened, so that torque can be transferred before it was needed.[7][8] This improvement meant the system could operate more like other "always-on" full-time four-wheel drive systems as it no longer had to "wait" for traction loss to take action.[8] Another improvement was front-to-rear "torque biasing" capability in Auto mode. ControlTrac's intelligent multi-disc differential could now send all 100 percent of the engine’s torque forward, biasing it to the front differential if severe traction loss was anticipated, predicted, or detected.[8]

Good stuff! I have only had my 2017 since mid December, only needed the 4WD once or twice this winter. I distinctly remember in my 05 a noticeable shift when in 4 Auto. Not sure if it was the Transfer case, or the hubs engaging. There would be a slight slip, then the front axle would engage. I'm sure the system has been refined from 05 to 17. This definitely explains why when I took the 17 out the first time in the snow, I felt absolutely nothing when in 4 Auto. Just smooth, confident traction

 

[Plati]

I think this is the article from Design News that got me to buy my first Expy.

https://www.designnews.com/automotive-0/4-wheel-drive-steps-back-future/143802243139748

in other news , its still snowing here!!!!
WTF

 

[JExpedition07]

Good stuff! I have only had my 2017 since mid December, only needed the 4WD once or twice this winter. I distinctly remember in my 05 a noticeable shift when in 4 Auto. Not sure if it was the Transfer case, or the hubs engaging. There would be a slight slip, then the front axle would engage. I'm sure the system has been refined from 05 to 17. This definitely explains why when I took the 17 out the first time in the snow, I felt absolutely nothing when in 4 Auto. Just smooth, confident traction

In my 07’ you can’t hear or feel anything you just know because in 4A you can gas it pretty good and it still won’t slip out like in 2H.

 

[Boose]

In my 07’ you can’t hear or feel anything you just know because in 4A you can gas it pretty good and it still won’t slip out like in 2H.

Now I'm wondering if there was something not quite right with my old truck... Maybe someone with an 04-06 can confirm what theirs is doing...

 

[Boose]

I think this is the article from Design News that got me to buy my first Expy.

https://www.designnews.com/automotive-0/4-wheel-drive-steps-back-future/143802243139748

in other news , its still snowing here!!!!
WTF

This makes sense:

"Called Control Trac by Ford, it acts as an automatic form of four-wheel drive. Using sensors, microprocessors, and a specially designed electromagnetic clutch, the unit quickly switches from two-to four-wheel drive when it senses wheel slip."

That is what I experienced... granted, this article was written in 1995. My 05 would take about a half of a rotation of the rear tires in order to engage the front axle while in 4A.

 

[JExpedition07]

This makes sense:

"Called Control Trac by Ford, it acts as an automatic form of four-wheel drive. Using sensors, microprocessors, and a specially designed electromagnetic clutch, the unit quickly switches from two-to four-wheel drive when it senses wheel slip."

That is what I experienced... granted, this article was written in 1995. My 05 would take about a half of a rotation of the rear tires in order to engage the front axle while in 4A.

Our 3rd gens have the ControlTrac II system.... your 05 was a 2nd gen and may have had the first ControlTrac system.

 

[ExpeditionAndy]

A shiny new nickel at that

LOL!