Why No Full-time AWD Pick Ups?
 

My wife and myself have always been very happy with the FDAWD's in our various Subarus over the years - and our current Wilderness edition Outback is superb in snow - especially as we've switched out our (already great) AT tires for Blizzaks.

It would seem obvious that such an AWD system would make perfect sense in a pickup truck - so...why does such an animal not exist? Load thresholds? Suspension dynamics? Something else?

Good question. I'm looking forward to the responses.

Maybe I am misunderstanding the question. However, my Honda Ridgeline is full time all wheel drive.

Mostly marketing I would guess. My Silverado Z71 is listed as 4X4 but it has several choices including dedicated 4X2, 4X4 Low, 4X4 High, and "Auto" which as I understand it is adaptive AWD you can use every day. This is probably the equivalent of a Subaru AWD mode on a Z71 truck that just "sounds" more gnarly because... Truck.

There have been a few over the years, particularly higher trim levels. My Ram Limited has a 4wd Auto feature where it automatically proportions power depending on the conditions, much like an AWD system. I suspect it’s more of an “on/off” than actively adjusting power to the front wheels.

Traditional 4wd uses a transfer case and sends the same power front and rear to maximize traction. It’s really only intended for adverse conditions and typically more mechanically robust. AWD typically works through some variety of viscous center differential that automatically proportions power front and rear. It’s a similar concept but less robust and better suited for on road use.

Interesting. Gas mileage?

I think it is also vehicle size related...just based on my old Land Cruiser with FTFWD and my ten year old Tundra.

The difference in vehicle size is significant. In 4x4 Hi, the turning radius on the Tundra is significantly reduced...f' it I have really have no idea:cool:

Gas mileage is another good reason, AWD systems operate a lot like 2wd in most conditions. Some decouple the other two wheels to minimize drag and fuel use. True 4wd the power is going 50/50 front and rear whether you need it or not.

Yep, it is mostly the gas mileage issue. The corporate fuel economy laws make it so.

Some other considerations other than gas mileage:

AWD systems (like Audi's early quattro before all the electronic shenanigans and Subie's AWD systems) are based on feeding power to a center differential which in turn sends power front and back. There are a few vehicle design attributes that make this a good fit on cars: All the wheels are generally on the ground at the same time / limited body twist, you don't have extreme turning angles, and vehicle load front/back is relatively constant.

Pickups have some load cases that occur more frequently. You're frequently getting into larger steering angles which can cause binding in the front diff and force wheel slip (I get this frequently when in 4WD with my truck on slippery surfaces). Trucks, when off-road, may tend to lift a tire on one axle; the transfer case (with no center diff) will still still be sending power to the other axle to pull you through that while the axle with a lifted tire is spinning a wheel. A center diff may just bias all the power to the spinning axle. (Yes, you can limited-slip center diffs and front/rear diffs, but these tend to wear quickly and have high service requirements on pickups.)

it's not needed. Drove through snowstorm this am to hunt and either wanted 4wd fully (ie no 'oh it slipped let me get those front wheels turning for you') stuff or 2wd.

I suspect also such a system might not be as durable on a heavy vehicle towing heavy weight.

Ford Maverick AWD, Hyundai Santa Cruz and as mentioned the Honda Ridgeline. Subaru is allegedly coming back out with the Baja

Like Paul my Land Cruiser is full time 4wd and fuel economy definitely suffers.

My TRX was full-time 4WD.

GM had auto 4th in 1/2 tons.., maybe they still do.

My 73 Blazer was full time 4wd but also featured a low range. It got 10.0 MPG. But looked damn good doing so. Pea green with a full convertible top. Sure miss that rig.

The Tesla Cyber truck is full time AWD with a towing capacity of 11,000 lb.s

That's the clincher ... but now I gotta find a 10,000 lb redonkulous trailer too :D!

Of course, you have a real-world range towing 11,000# of about 100 yards, but I digress .... :D

I think the real question is 'what is AWD vs 4WD today?'. The answer used to be clear. It hasn't been for the last 10+ years and it's now more of an exercise in semantics. The original AWD system of the early 80s (the quattro) was extremely simple - a front, rear, and center mechanical differential. So all 4 wheels could be driven all the time even on dry pavement. Today? You've got very sophisticated systems tied into the ABS and other sensors that instantaneously provide drive to each wheel with the result being the same (or better) than so-called AWD. In trucks, it's usually called 4A (4 wheel drive automatic) but can vary substantially in how it's accomplished and how it feels to the driver.

http://forums.pelicanparts.com/uploa...1736690286.jpg

I'll put a charging station at the horse barn ... I don't have any horses tho'... might get something practical .... Zebras :)

I was surprised when shopping half tons early last year to see some with 4 auto. My F150 hybrid is a Lariat trim and has 4 auto, 4 hi, 4 lo and 2h. I just leave it in 4 auto all winter. It's nice to have where we live where. Winter can be long with snow/ice on the streets for long periods, and it's my daily driver. Switching in/out of 4wd depending on pavement conditions can be a pain. Often the arterials here are de-iced, the other neighborhood roads are not.