2014 Limited four-wheel drive questions

[spm]

I have a 2014 Limited with the full-time 4WD. My questions are how does the full-time work and what do the letters on the control switch mean? I know what the different positions do, I just want to know what the letters stand for. I have looked in the manual and run a search on this forum and can't find anything.

1.
A friend told me that when the transfer case is unlocked it delivers 20% to the front wheels and 80% to the rear. Is this correct? If not, how does it work?

2.
H4H - Normal driving. What do the letters stand for? Why two "H"s?
H4L - 4WD High - Again, what does the H stand for? High range? Since this is high range 4WD what does the L stand for?
L4L - 4WD Low range - I assume, again one "L" stands for low, but why the other L?

Thanks,
spm

 

[Orc]

Read the manual. My understanding is it has a center diff so it's like a subaru STi it can lock for more real 4x4

 

[1engineer]

I have a 2014 Limited with the full-time 4WD. My questions are how does the full-time work and what do the letters on the control switch mean? I know what the different positions do, I just want to know what the letters stand for. I have looked in the manual and run a search on this forum and can't find anything.

1.
A friend told me that when the transfer case is unlocked it delivers 20% to the front wheels and 80% to the rear. Is this correct? If not, how does it work?

2.
H4H - Normal driving. What do the letters stand for? Why two "H"s?
H4L - 4WD High - Again, what does the H stand for? High range? Since this is high range 4WD what does the L stand for?
L4L - 4WD Low range - I assume, again one "L" stands for low, but why the other L?

Thanks,
spm

Read the "How Does the 5th Gen 4WD Work" link in my signature.

 

[bimrunner]

H4H- normal driving means that gearing is all "normal" and the system can select the highest gear for given power, torque and distribution for the way that it was programed to work under normal everyday driving conditions.

H4L- this is when the center diff is locked and power is locked into being distributed evenly between the front and rear diffs. You wouldn't need this under normal driving conditions and should be used in low traction situations only such as dirt, snow etc, but is allows for the system to select all gears - even high gears for higher speed with lower revs.

L4L- this is when the center diff is locked and the gears are locked out of using higher gears in order to make sure maximum power transfer (torque) is delivered evenly between the front and rear axles. This is for more extreme low traction driving such as rock obstacles, mud, sand... You won't be able to drive at high speeds and gear shifting is done at much much higher revs than H4L and H4H.

Think of the first letter as referring to gear setting and second letter as referring to center diff being open or locked. On the LE you are always getting some power to all 4 wheels (with some exceptions but that isn't the point here) and hence all the options have a 4 in it.

This is my attempt to make it simple, but really nothing is more simple than what the manual says...

 

[Intruder]

H4L - 4WD High - Again, what does the H stand for? High range? Since this is high range 4WD what does the L stand for?
L4L - 4WD Low range - I assume, again one "L" stands for low, but why the other L?

Second L in both probably stands for Locked, as in the centre diff is locked.

 

[1engineer]

Second L in both probably stands for Locked, as in the centre diff is locked.

IF there is a second "L", THEN it must mean "Locked."


(man my attempt at humor sucks.)

 

[SouthernSS]

The center diff lock is, imo, a great feature. It guarantees that at least 1 front wheel and 1 rear wheel will spin at the same rate. Couple this with Atrac and you've got an incredibly capable stock vehicle. Dont EVER use it on pavement though, or you WILL break something in the driveline.

The GX470 is also an all time 4wd truck with the center diff lock and there hasnt been a single obstacle I've pointed that truck at it couldnt crawl over with the help from some electronic wizardry. This includes some Level 5 trails I had no business being on , lol.

 

[proquip]

I have a 2014 Limited with the full-time 4WD. My questions are how does the full-time work and what do the letters on the control switch mean? I know what the different positions do, I just want to know what the letters stand for. I have looked in the manual and run a search on this forum and can't find anything.

1.
A friend told me that when the transfer case is unlocked it delivers 20% to the front wheels and 80% to the rear. Is this correct? If not, how does it work?

2.
H4H - Normal driving. What do the letters stand for? Why two "H"s?
H4L - 4WD High - Again, what does the H stand for? High range? Since this is high range 4WD what does the L stand for?
L4L - 4WD Low range - I assume, again one "L" stands for low, but why the other L?

Thanks,
spm

[MENTION=113159]spm[/MENTION] I don't think the first option is H4H, but rather H4F

H4F is high (H) range 4WD, unlocked center diff, full-time (F) 4WD. You should be in H4F for everyday driving.

H4L is high (H) range 4WD, locked (L) center diff. It behaves similar to a part time 4WD. Power is distributed to both front and rear axles 50/50. Use H4L on slippery surfaces to prevent binding of the drivetrain.

L4L is low (L) range 4WD, locked (L) center diff. Similar to H4L, except it's in low range and it provides much more torque to the wheels to aid in low traction surfaces.

 

[Bilbo]

I have a 2014 Limited with the full-time 4WD. My questions are how does the full-time work and what do the letters on the control switch mean? I know what the different positions do, I just want to know what the letters stand for. I have looked in the manual and run a search on this forum and can't find anything.

1.
A friend told me that when the transfer case is unlocked it delivers 20% to the front wheels and 80% to the rear. Is this correct? If not, how does it work?

2.
H4H - Normal driving. What do the letters stand for? Why two "H"s?
H4L - 4WD High - Again, what does the H stand for? High range? Since this is high range 4WD what does the L stand for?
L4L - 4WD Low range - I assume, again one "L" stands for low, but why the other L?

Thanks,
spm

The designations are:
H4F: High speed, 4-wheel drive, Free center diff
H4L: High speed, 4-wheel drive, Locked center diff
L4L: Low speed, 4-wheel drive, Locked center diff

According to the 2014 4Runner Product Information Sheet, the normal unlocked center diff split is 40% front and 60% rear. As needed, this can range from 30-70 to 53-47.

You can find the sheet here:
2014 Toyota 4Runner Product Information | Toyota

 

[BobsTrail]

Good input above, I`m surprised no one sent this:

:rtfm:

Search YouTube, there are many good videos about our 4Runners, from reviews, to explanations and off road videos.

 

[Jeremy556]

The center diff lock is, imo, a great feature. It guarantees that at least 1 front wheel and 1 rear wheel will spin at the same rate. Couple this with Atrac and you've got an incredibly capable stock vehicle. Dont EVER use it on pavement though, or you WILL break something in the driveline.

Not so much. It's unlikely that you would ever need to use the center diff lock on pavement, but it is the same as any standard 4WD vehicle being in 4HI on pavement. You'll get driveline bind making parking lot turns, but it's very unlikely you're going to break anything.

 

[SouthernSS]

Well I've seen it happen during a test drive that ended early because my friend who was unaware of what that button did, pressed it while at a stop light to turn left. As he went to take off we heard some popping/clicking tire chirping that got louder as the turn radius got tighter until POW and a jolt. Im not eactly certain what teeth were sheared where, but it wasnt drivable anymore and had to be towed back to the dealership.

Luckily they didnt fault him for it, but I certainly wont be trying it on my truck on dry pavement.

 

[crackiswack]

Well I've seen it happen during a test drive that ended early because my friend who was unaware of what that button did, pressed it while at a stop light to turn left. As he went to take off we heard some popping/clicking tire chirping that got louder as the turn radius got tighter until POW and a jolt. Im not eactly certain what teeth were sheared where, but it wasnt drivable anymore and had to be towed back to the dealership.

Luckily they didnt fault him for it, but I certainly wont be trying it on my truck on dry pavement.

The car manual says its fine, since they recommend putting it in 4wd for 10 miles a month. I've done it on some roads where there is alternating pavement and gravel and never get binding.

 

[SouthernSS]

Yes, operating in 4wd with open differentials is quite different than operating in 4wd with a locked center diff. I do try to exercise my 4runners 4wd once a month on the road, but I'll never engage my rear locker unless I'm off the pavement.

But hey, to each his own. It is your $35k+ machine you're risking, not mine. You could drive around all the time with a locked differential and never get anything more than tire chirp, or it could grenade your diff and leave you on the side of the road. Your choice.

 

[Jeremy556]

Yes, operating in 4wd with open differentials is quite different than operating in 4wd with a locked center diff. I do try to exercise my 4runners 4wd once a month on the road, but I'll never engage my rear locker unless I'm off the pavement.

But hey, to each his own. It is your $35k+ machine you're risking, not mine. You could drive around all the time with a locked differential and never get anything more than tire chirp, or it could grenade your diff and leave you on the side of the road. Your choice.

Actually, it's pretty much the same. Both drive shafts turn at the same rate. I can't imagine the center diff is so fragile it blows up by making a left hand turn on pavement.

I drive on slickrock all the time (higher grip than most pavement) in 4wd (both drive shafts turning at the same rate). Tires chirp and squeal, but haven't broken anything in the driveline, yet.

 

[spm]

[MENTION=113159]spm[/MENTION] I don't think the first option is H4H, but rather H4F

H4F is high (H) range 4WD, unlocked center diff, full-time (F) 4WD. You should be in H4F for everyday driving.

H4L is high (H) range 4WD, locked (L) center diff. It behaves similar to a part time 4WD. Power is distributed to both front and rear axles 50/50. Use H4L on slippery surfaces to prevent binding of the drivetrain.

L4L is low (L) range 4WD, locked (L) center diff. Similar to H4L, except it's in low range and it provides much more torque to the wheels to aid in low traction surfaces.

THANK YOU PROQUIP!
You are the first person to actually read the question and answer it. And you are correct, I mis-quoted that first setting.

Now, does anyone actually know what percent power goes to the front wheels and what percent power goes to the rear wheels in the H4F setting?

Thanks to all for your help.
spm

 

[BobsTrail]

4H on pavement

I have put mine in 4H on my cement driveway and made a gentle turn and I can feel the binding in a very short distance. It will not creep forward in drive with no throttle imput like it does normally. 4H for straight roads only or off road for me.

 

[SouthernSS]

Actually, it's pretty much the same. Both drive shafts turn at the same rate. I can't imagine the center diff is so fragile it blows up by making a left hand turn on pavement.

I drive on slickrock all the time (higher grip than most pavement) in 4wd (both drive shafts turning at the same rate). Tires chirp and squeal, but haven't broken anything in the driveline, yet.

Actually no, its not the same.

Borrowed from member JB:

"With a locked center connection -- part-time 4WD (classic 4WD) or full-time 4WD with center differential locked (cdl on) -- the front and rear drive shafts rotate at the same speed, just as if there were one shaft from front to back. During a turn, all four wheels turn in a different size arc and, thus, different speeds. This can't be compensated for by the front and rear diffs because when each side of the diff has traction, any increase in speed on one side is matched by an equal reduction on the other side. Since it's the average speed of the two front wheels and the average speed of the two rear wheels that matters, the effective result is a comparison of one arc for the fronts and one arc for the rears. So, during a turn the rear wheels follow a smaller arc (1 averaged arc) than the fronts and want to turn more slowly. The locked drive shaft in between can only rotate at one speed so opposite forces are created between front and back, with the braking force (skid) being in the front and the drive force (slip) in the rear. With same size tires equally inflated, this conflict is near zero when the vehicle is going straight, but starts to come into play as the steering wheel is turned, starting out mild but quickly becoming more severe as the turn is made tighter, resulting in an increasingly heavy feel in the steering wheel and a sensation of brakes being applied. Near the extremes, tires can audibly and visibly skip and skid. On slippery surfaces, this can occur more easily but on pavement more stress is imparted to the drive train, especially at very low speed where releasing energy through the tires is more difficult and there is no momentum to unweight the inside tires during a turn. It also results in handling changes that usually make the car want to turn a little wider (understeer) than it normally would, due to the tendency of a front wheel to skid. (The words bind and windup, in combination with various parts of the drive line - differential, transfer case, axle, transmission - are terms often used to describe this phenomenon. In other domains, a separate phrase - Tight Corner Braking - is also widely used)."

 

[03_4x4Runner]

It is to bad Toyota did away with the choice of center diff unlocked in low range like the 4th gens have. This was great for pulling heavy boats out of slippery boat ramps on pavement in low and not have the driveline binding. Also worked great in low range off road 95% of the time with no binding. If someone was creative some wiring changes and a new switch this feature could probably be added to the 5th gen Limited.

 

[Jeremy556]

Actually no, its not the same.

Borrowed from member JB:

"With a locked center connection -- part-time 4WD (classic 4WD) or full-time 4WD with center differential locked (cdl on) -- the front and rear drive shafts rotate at the same speed, just as if there were one shaft from front to back. During a turn, all four wheels turn in a different size arc and, thus, different speeds. This can't be compensated for by the front and rear diffs because when each side of the diff has traction, any increase in speed on one side is matched by an equal reduction on the other side. Since it's the average speed of the two front wheels and the average speed of the two rear wheels that matters, the effective result is a comparison of one arc for the fronts and one arc for the rears. So, during a turn the rear wheels follow a smaller arc (1 averaged arc) than the fronts and want to turn more slowly. The locked drive shaft in between can only rotate at one speed so opposite forces are created between front and back, with the braking force (skid) being in the front and the drive force (slip) in the rear. With same size tires equally inflated, this conflict is near zero when the vehicle is going straight, but starts to come into play as the steering wheel is turned, starting out mild but quickly becoming more severe as the turn is made tighter, resulting in an increasingly heavy feel in the steering wheel and a sensation of brakes being applied. Near the extremes, tires can audibly and visibly skip and skid. On slippery surfaces, this can occur more easily but on pavement more stress is imparted to the drive train, especially at very low speed where releasing energy through the tires is more difficult and there is no momentum to unweight the inside tires during a turn. It also results in handling changes that usually make the car want to turn a little wider (understeer) than it normally would, due to the tendency of a front wheel to skid. (The words bind and windup, in combination with various parts of the drive line - differential, transfer case, axle, transmission - are terms often used to describe this phenomenon. In other domains, a separate phrase - Tight Corner Braking - is also widely used)."

I am talking about the part underlined above, that a center locked AWD and a part time 4WD work the same - both drive shafts turn at the same speed. I agree with everything in JB's post, actually.