tvsjr

That system is no different than the AWD system used in the AWD Explorer and Taurus. It is *not* capable of sending 100% of the torque to the rear wheels. Watch the power distribution graph (if the Taurus PI gives you this option) and you'll never see it transfer 100%.

That system is also the hidden flaw in those vehicles... the Power Transfer Unit (PTU) is pretty damn fragile. Abusing it, or tuning the vehicle and sending too much power through the PTU, will commonly destroy them. I've got a 2017 Explorer Sport sitting in my driveway, and that's one of the big reasons it's never been tuned.

duck9191

I love the awd in my jeep in the winter, hate it the rest of the year. It's not a fancy system, just a gearator clutch in the transfer case but its sensitive. It's very hard on tires and tanks the gas mileage. If i keep it im swapping transfer cases back to a part time tc. The new systems can do a bunch of tricks, but they are all going to add additional maintenance at some point down the road, plus designing them to told up to some ******** towing the full rated capacity spinning the tires is probably a bit tricky. I honestly wouldn't mind the 4A option in my truck, especially for when my wife drives it.

65Terdlingua

The 4A transfer case in F150's uses a clutch to engage the front axle when slip is detected. The rear is always engaged, the front can be fully engaged for a max of 50/50. The front end will never be driven with more torque than the rear.

montanaman

http://www.hendonpub.com/resources/article_archive/results/details?id=5091

This is worth a read.

Crazy Canuk

The last generation of GMC Full size (Sierra and Yukon) Denalis were AWD. The new ones are switchable two speed transfer cases with 4A.

My 2011 Limited had a 1 speed transfer case. The options were 2wd, AWD and 4Hi.

casique

I believe the Honda Ridgeline city-truck has an AWD system. MY wife's Acura MDX has an AWD system and gets great gas mileage. She averages about 20 in the city and about 28 on the HWY.

l3rian

My buddy had a Silverado SS that was AWD. So AWD systems can be designed for the power and weight of a full size truck. If I remember right, it didn't have low range at all.

mrv99

My pavement pounder only sees snow 10-15 times a year so to me why have AWD when I don't need it 330 days a year

ThunderStruck007

OP here again -
I wanted to chime in again.

I also have a RWD BMW, but I know about BMW's AWD system quite well. It is RWD-biased meaning, it acts like a RWD car unless the car detects slip, at which point can send up to 50% of power to the front wheels.
I believe Mercedes benz's system works in a similar fashion.

I think subaru's awd is more like Audis, which are more "true" AWD cars. Atleast, that is how I understand it.

Now, as a BMW fanboy, they just released a new BMW M5 with over 600HP/600TQ... also, there are a ton of super-high performance cars that are AWD.
They dont seem to tear themselves apart, and the torque isn't too much for the system - so, in theory at least, someone should be able to make an AWD truck capable of towing heavy loads.

Yes AWD systems are heavy. There are more moving parts, and more chance of something breaking, and more maintenance.
But that is just like the people that say an EcoBoost truck has more moving parts, etc... doesn't mean it will be any more or less reliable in my opinion.

But AWD will hurt MPG which I think is probably the main, if only, reason.

I NEVER knew about the 4A option in the higher end trucks...
Looking back, had I known that, I would've gotten a Lariat instead of my XLT. Between LED headlights, leather, and now 4A... I want a new truck

BlackBoost

You can't put more than 50% power to the front, so 50-rear/50-front is the max, but it can go 100-rear/0-front and anywhere in between.
It also doesn't vary torque to each axle, it can only vary torque to the front axle. Rear can't be changed.

EDIT: Beat me to it, and you are correct.