Why no 4WD Auto / Multi-Mode?

When sections of the road are shaded from the sun with ice/snow/slippery, but good traction in sunny sections...For better traction and safety...in an unloaded pickup truck...

Why didn't Toyota include a user selectable four wheel drive auto multimode, for 4WD in the above scenario, with a center differential between the axles to prevent drive train binding?

Is automated 4WD switching too unpredictable to be safe?

Did Toyota provide a better solution on the 2022 Tundra?

Or is multimode not all that great in reality?

 

No one knows. We've been begging for it since GM introduced it in 2007.

 

I loved it on my 05 Silverado for rain. Think it helped for hydroplaning.

 

Tommy Mica at TFL truck said in one of their videos that one of the vehicles they were testing was in Auto (4A) AWD not 4WD (forget if it was a Ford or Chevy product) and the vehicle was spinning it’s wheels and did not know what to do as if it was in 2WD, he was baffled and said……. Not sure what the Auto feature does….. I will try to find the video when I get some time. This is just my opinion but perhaps Auto AWD does not work as well as it should and Toyota doesn’t play that game….

 

I gotta agree, never had any real need for it. And I had come across those changes frequently over the years. For better traction but ESPECIALLY for safety, drive at moderate speed and keep your distance. I will take patience any day of the week over auto 4wd. Over the years I only really use 4x4 on the road because you either have the idiots thinking their 4x4 is king of the mountain driving at 60 mph in a blizzard or the idiot driving 5 mph on a snowy incline and wondering why they are not getting traction. I absolutely love driving in the snow but I hate other driver’s in my area because the are mostly Komakaze pilot’s…

 

My 1988 Jeep Cherokee Limited when it was owned by AMC had it.
When TFL Andre was interviewing one the Engineers he asked about it, and the Engineer said that MTS is now part of 4HI also.
Its not 4Auto but better than not having it - if it works 8^0

I think that what you said is consistent with people I have talked to about it in the past. Maybe coincidence but everyone I have ever talked to that is comfortable with 4wd have told me they like to put it in 4wd themselves. I have also talked to people that do not trust 4Auto.
My personal experience is 4 auto is not as good as AWD like the Subaru systems.
AWD is all wheels all the time. 4 auto needs the front or back (depending on drive) to start slipping before it engages and sends more torque to the front or the back.

IMO. Another clue to the way Toyota thinks may be to look at the 4Runners. In Canada anyway the luxury models have full time 4wd no rear diff locks.
The Offroad models and the TRD Pro have part time 4wd with rear diff locks.

If I was using my vehicle as a daily driver through winters where the roads are sketchy like the OP said - I would want AWD in the vehicle.

 

I believe the brake actuating traction control does an excellent job. My 2012 Tacoma and my current Tundra was much easier to control from takeoff in the snow and rain than my 2003 and 1998 Tacoma’s with no traction controls. I was honestly surprised at how well the Tundra does. The other key point here is tire selection. Every BfGoorich and Goodyear truck tire became like a racing slick in the rain and inclement weather after a couple of years of use. Hence why I fell in love with Michelin truck tires. Auto 4wd may very well be beneficial but I feel very confident driving my Tundra in the snow at moderate speeds. But that’s just me…

 

In my scenario that could mean manually selecting 4WD/2WD several times in a commute. Sometimes the road conditions benefit from 4WD and sometimes not. Sometimes the road has snow/ice (shaded areas, no plow/sand), sometimes it doesn't (sunny areas or it got plowed/sanded). I didn't like manually selecting 4WD on/off through my commute.

 

I own a 2018 Tundra with part time 4wd and just moved to the Chicago area from Houston about a year and a half ago. I thought I was good in winter with the 4wd in the Tundra but like you said, there were many times I would go on roads that were partially iced and the rest would be dry and it got really tedious turning the 4wd off and on. I really did not like it!!!. Almost rendered it useless to be honest.

I ended up buying a 2022 Lexus GX460 as it’s full time 4wd and also has a lockable center differential as well as 4Lo so I have all my bases covered. I can’t even tell you how much more I enjoy driving the GX in bad weather. There are also other times where I didn’t even know 4wd would be beneficial like in rain, mud dirt and other things I didn’t even know about.

I really wish they would have at least put auto 4wd on the new Tundra. That was one of the main features I was looking forward to. Oh well!.

 

Dealt with this yesterday and I’ll deal with it all winter long. Switching back and forth, wondering if I should be in 4wd or not. Questionable roads all winter long here.

4wd sucks for actual winter driving compared to AWD. I love our outback for this reason, much prefer to take that on crappy roads

 

Yes, Auto 4wd is great.
I have it on my 2000 Silverado, wife’s 2015 Suburban, and 2021 Company Tahoe.
Had it on my 2002 Explorer and 2016 Expedition EL.

It is great especially in the rain and light snow.
If you know you are going to need 4WD you put it in of course.

It is very much a down fall on the Tundra not having it. That and the craptastic electronic LSD are about the only two things that are seriously disappointing about the Tundra.

 

Hydroplaning is more of a tire tread issue where the tread can't channel away the water so that the tire can then make contact with the road surface.

 

I love the Multimode AWD and center lock diff 4wd in my 2002 4runner.

 

If you're not comfortable driving in changing conditions then I feel you shouldn't be driving in it. By the time system catches on that it needs to switch 4wd on I feel whatever the situation you are in you're pretty much screwed anyways. Again this is my opinion. I've been driving 4wd trucks for decades and when ever I feel conditions are changing rapidly or I'm just not sure I change speed and most of the time just put it on 4wd. I've lived in Seattle with rain, occasionally snows, went to the mountains alot so I learned alot growing up, I now live in Denver, so I've gone through a bunch of changing conditions and never thought oh I wish I had 4wd auto. So again my opinion I'm glad toyota didn't offer it. Might as well get a awd suv. Again everyone has what they like and that's fine, I'm not here to change people's mind. Anyways happy holidays to all and I hope everyone gets the truck they want.

 

Totally agree. This system is the best, but they dropped it for cost saving on the 5th gen 4NRs. With the 4th gen 4RNR multimode and center diff lock, you could keep in 2wd or switch to awd or hit the center diff lock and acted like a part time 4wd system. Way better than the tundras part time only system

5th gen 4RNR have a part time 4wd system except for limited which is awd all the time

toyota knows how to do it, wish they would bring it back and give us the option.

 

Well yeah that’s what I do too as a good driver, slow down and put it in 4wd.

But AWD is pretty nice man, it’s ok to like it. Doesn’t make ya less of man.

pretty nice with drifting snow and the like on rural roads where lots of the pavement is dry, taking off from slick stop signs on busy county roads where most of the pavement is dry for examples

 

Almost that time of year when my Tundra gets stuck in my snow covered New England driveway and uphill road until I put it in 4HI and my wifes X3 M40i on Pirelli P-Zero summer tires and all wheel drive embarrasses me (well at least until I use 4HI). Deep snow she's gonna get stuck before me and not be able to get out even with winter tires but most of the time roads are plowed and AWD/fulltime 4WD just becomes more of a safety net. Honestly I would love a full time 4WD option (and the tech is there since it's in the Sequoia) but I think to Toyota it's a marketing thing for some reason.

Also her X3 M40i even on summer tires is a damn snowmobile provided the snow isn't high enough for it to become a plow. Bavarians know how to make sports cars (and SUV's, SAV's whatever they call them now) that look super unpractical in winter conditions but mostly kinda don't suck. Few years ago she had a X5 diesel on snow tires and that thing was an absolute beast in the snow.

 

I've used both extensively in horrible midwest winters.

From my own personal experience, 4auto is quite useless.

At each start of a new winter season I see a lot of trucks in ditches. I do all I can to make sure I'm not one of them.

I am sure you fellows do an amazing job driving in 4auto. That's great but with the roads I use it just doesn't work as good as 4HI.

I am grateful that Toyota is not offering 4auto.

 

To each his own. I think it's a pointless option for a truck. Not trying to be macho.

 

I'm not a mechanic, so could easily be wrong, but when you say Auto 4WD you mean AWD? All wheel drive controls power to each of the wheels independently, with some transfercase/differential magic, which is great for on road traction improvement. With 4WD the power distribution to each differential is fixed, so on dry pavement with good traction you get wheel binding. In 4WD you get power applied to all 4 wheels, all the time, which improves the ability to get through more extreme off-road low traction situations. Seems like can't get the best of both worlds, a system that maybe engages 4HI automatically when wheel slip is detected sounds gimicky, like cylinder de-activation. Plus the delay in the hubs locking, would they need to be always locked to the drive shaft, so the differential would need to be limited slip(or something like that), which isn't the best for off-road performance.

 

Our 04 Grand Cherokee had it, and it worked well amd was pretty nice, especially for the wife.

When we lived up north, I can say confidently the trucks in ditches were not the fault of AWD, 2WD or even 4WD systems... it was because people seem to forget the laws of traction on slick surfaces over the summer months. It comes back to them once they land in the ditch on the first snow, then they're OK again until next year.

 

No, auto means you're in 2wd and when the wheels slip the system will engage 4wd. That's it in a nut shell. Also if you fit some reason don't want to turn a dial to 4wd you just leave it in auto. Awd means all wheels are engaged with more power going to the front most of the time. My truck is a 4wd. Technically called part time 4wd.

 

Born Warner makes two basic transfer cases used in most half ton trucks. One they call shift on the fly (SOTF) and one is torque on demand (TOD). The SOTF has a chain between the rear and front output yokes. The chain rides ride on gears with shifter forks and couplers to lock those shafts together or not. Ford XLTs and below and Toyotas uses that transfer case. Lower end Rams also use that transfer case. The TOD transfer case has clutch plates and a electro-magnet pressure plate to lock the front and rear output yokes together. High pressure is a near full lock and low pressure allows for a lot of slip. The vehicle computer adjusts the pressure based on speed differences between the front and rear yokes or driveshafts.

Both have their pro's and con's. The TOD unit is really great for mixed road conditions and will keep you from fish tailing going up hills, helps with starting off from stops, etc.. The TOD unit major con is in situations where you want a mechanical lock because you'll be spinning your tires a lot like sand or mud etc... The clutch plates will heat up from the slip that occurs even at full pressure.

There are other systems out there but most are torque limited and not found in pickup trucks. My last Platinum F150 had the TOD unit and I really liked it in CO. I don't 4-wheel full size pickups so it worked well for me. My current tundra has the SOTF unit and I do find myself shifting in and out a lot...a bit of a PITA but nothing that I can't live with. Why Toyota didn't offer the TOD on Platinums/1794s I have no idea. Maybe they just didn't want more complexity in the supply/manufacturing chain or maybe they didn't want the the TOD cons over time.

Borq Warner are experts at transfer cases and pretty much have the market cornered on light duty full size trucks.

 

Yeah I get it, I love my truck too with just 4wd.

guess I’m talking about AWD more then 4 auto. Can’t help but to gush over my wife’s outback whenever I can

 

There’s no arguing that AWD is amazing in the snow. My wife’s Highlander and my commuter RAV4 are tanks in the snow. Unfortunately auto 4wd simply doesn’t compare. But I would chose my Tundra when the snow is deep enough to scrape the undercarriage which is where 4wd shines in my opinion.

 

The trucks I've seen with 4Auto still have 4Hi (and sometimes 4Lo - looking at you GM) so you can pick your poison.

 

And yet the big 3 have had it for years.

If you want something less "gimmicky", I'd settle for the full time 4wd the Sequoia and 4R get.