Limited's Full-Time 4WD Like AWD?

[ThePirate]

I have a question about the 2012 limited's 4WD system.

It's a full-time 4WD system. Does that mean when the selector knob is at H4F that it operates like an AWD system where it may not be a 50/50 split of power between the front and rear axles, where 80-90% of the power may be sent to the rear axle and more is sent to the front only when needed?

The owner's manual says that H4F (center differential unlocked) should be used for driving on "dry hard surface roads." I would hope that in H4F it would be good in light snow and ice too. Isn't that the benefit of having full-time 4WD; you don't have to worry about shifting it in and out of 4WD because of patchy snow and ice on an otherwise dry asphalt road?

It sounds like when it's put into H4L (center differential locked), the power is now split 50/50 between the front and rear axles, and it's the most stable, even more than H4F.

Is having it in H4F a very good system for snow and ice covered roads too?

 

[DannyLlama]

Oh boy, this should be fun to watch... :snacker:

 

[bimrunner]

That is my understanding and past experience with 4wd full time, although I just got my '13 and haven't tried it out yet in snow etc. Plan to get up there in a few weeks. I assume you only would switch in really thick snow or off-road. Someone can correct me if I'm wrong.

 

[NorthWest 4R]

I have a question about the 2012 limited's 4WD system.

It's a full-time 4WD system. Does that mean when the selector knob is at H4F that it operates like an AWD system where it may not be a 50/50 split of power between the front and rear axles, where 80-90% of the power may be sent to the rear axle and more is sent to the front only when needed?

Yes H4F AWD all the time, not 50/50

The owner's manual says that H4F (center differential unlocked) should be used for driving on "dry hard surface roads." I would hope that in H4F it would be good in light snow and ice too. Isn't that the benefit of having full-time 4WD; you don't have to worry about shifting it in and out of 4WD because of patchy snow and ice on an otherwise dry asphalt road?

For ice/snow patchy roads just leave it on H4F. Only select H4L if on fully covered snow/sand/mud/etc, where you know you wont cause binding

It sounds like when it's put into H4L (center differential locked), the power is now split 50/50 between the front and rear axles, and it it's the most stable, even more than H4F.

I am pretty sure H4L is 50/50 as is L4L, only use L4L under 15 MPH

Is having it in H4F a very good system for snow and ice covered roads too?

Hope this helps you :shrug:

 

[Okki]

Is having it in H4F a very good system for snow and ice covered roads too?

I'll focus on this part specifically since its the largest misconception out there. 4WD/AWD is NOT generally speaking a mitigating factor when driving on ice or partial ice (i.e. driver side on dry pavement and the passenger side on ice).

Front or rear wheel drive cars can use the power differential and traction to steer by use of the throttle; AWD type vehicles do not have that benefit. the resulting 4 wheel spinning due to loss of traction make the vehicle harder to control when mishandled.

Snow and ice are severely different driving conditions and should not be combined when evaluating the handling characteristics of any specific drive train.

The selection of which mode to operate in is fully dependent on the conditions you are driving in. 3 inches of snow will have you driving differently on a flat road versus a 7 degree hill with the same 3 inches of snow.

H4F = High gear "free" (unlocked) --> I call it "F"reeway mode.
H4L = Locked but high gear. This will drag a tire when making a tight turn and should only be used in required conditions and not as an 'always on" mode.
L4L = Low gear & locked (you have to be in neutral and press the button to switch to this mode or out of it). This is the low gear mode you will use when on off road trails or other road conditions that require high torque but low speed and again minimal tight turns.

Hope this helps.

Okki

 

[Ryan1975]

As a veteran of Upstate NY's horrendous winter of 09 with my 2008 4Runner allow me to describe how I approached driving in that truck (I've always lived in winter environs, not new to snow in 21yrs of driving).

If you're just driving around with 2-4" of snow or less should be no issue just leaving the truck in normal mode. Not until you're operating in some hairy stuff should you ever worry about switching. If you like to drift, feel free to engage the center diff. Once you shift you're locking the center diff to match the output speeds of the front and rear driveshafts. Since it's not a trail you have open front and rear differentials and your left and right tires are free to spin at different speeds.

I've thoroughly enjoyed my old 4Runner. Sliding sideways around corners at speed has always been fun. Recommend experimenting in the snow with unlocked center diff and with traction and stability controls turned off.

Unless you've run off the road, there shouldn't ever be a situation to run in 4Lo on normal streets.

Regards,

-Ryan

 

[Greg_Canada]

As a veteran of Upstate NY's horrendous winter of 09 with my 2008 4Runner allow me to describe how I approached driving in that truck (I've always lived in winter environs, not new to snow in 21yrs of driving).

If you're just driving around with 2-4" of snow or less should be no issue just leaving the truck in normal mode. Not until you're operating in some hairy stuff should you ever worry about switching. If you like to drift, feel free to engage the center diff. Once you shift you're locking the center diff to match the output speeds of the front and rear driveshafts. Since it's not a trail you have open front and rear differentials and your left and right tires are free to spin at different speeds.

I've thoroughly enjoyed my old 4Runner. Sliding sideways around corners at speed has always been fun. Recommend experimenting in the snow with unlocked center diff and with traction and stability controls turned off.

Unless you've run off the road, there shouldn't ever be a situation to run in 4Lo on normal streets.

Regards,

-Ryan

I agree with Ryan.

Fun fact,

In my 99 in H4F i notice it will not easily do donuts or spin out. When in H4L i can easily do powerslides / etc in the snow. When it snows, go to an open parking lot at night and get to know how each setting effects your driving / traction / turning. Plus it's fun as hell :hello:

 

[Galdarn]

Okki, Your reply is the best description I have found after lots of reading on the internet! Thank you for such a clear and to the point description.

 

[IanB]

Toyota's "Full Time 4WD" = AWD, it's crazy how many people struggle with this one!
H4L = 4x4
L4L = 4x4 low range.

AWD is fine to use anytime under any conditions. 4x4 can be used anytime there are slippery conditions, I use it when driving snow covered residential streets and find the truck is much less prone to understeer than when in AWD. And conversely, much easier to get it to oversteer, great for slides, donuts, etc!

On another note, it's a real shame ATRAC on these trucks only work when in L4L. On my GX470 it's always active.

 

[Layson]

You don't even need to go out of H4F. This thing is a machine in the snow. Literally foot to the floor and point it in the direction you want to go...LOL and it goes! Absolutely a great snow rig.

 

[ben550]

4Runner = snow monster. Incredible with right set of tires.

 

[Bossman]

Helpful video that explains the differences between Toyota's AWD versus 4WD and between part-time and full-time 4WD.

YouTube

 

[Orc]

I had owned a 2003 Tacoma TRD back in the day. Does anyone know if this had a AWD mode? If I remember right it had a button on the shifter that you just depressed for 4x4 but I'm not sure it it still had 4HI and 4LO that you moved that lever for...

 

[GreenMountainOwl]

Helpful video that explains the differences between Toyota's AWD versus 4WD and between part-time and full-time 4WD.

YouTube

That was great, thank you very much.

 

[IanB]

I had owned a 2003 Tacoma TRD back in the day. Does anyone know if this had a AWD mode? If I remember right it had a button on the shifter that you just depressed for 4x4 but I'm not sure it it still had 4HI and 4LO that you moved that lever for...

Tacoma's were 2hi/4hi/4low only, no AWD mode.