Center diff lock in H4!

[cloh09]

I don't know why it took me this long to figure out, but you can lock the center differential on the fly in 4high. I always thought I had to put it in 4low to lock it. I feel like a dummy but now that I know I can do this, wheeling around on the snow covered job site is easier and more fun! No more "granny mode."

 

[Metalmantr]

Cheers! 4Wd systems can be a quandary if you are not exactly familiar with them. Took me a little while to fully understand how to use it and their capabilities. Once I did, it is so awesome!

 

[dixie_boysles]

Cheers! 4Wd systems can be a quandary if you are not exactly familiar with them. Took me a little while to fully understand how to use it and their capabilities. Once I did, it is so awesome!

Speaking of, 4Runner 4x4 still has me baffled. (4) four wheel drive modes (4hi & lo unlocked)(4hi & lo locked).
I understand that only use the (locked) when off-road or low traction conditions but unlocked can still be used on dry conditions.....but how come?

I'm coming from Ford trucks that you have the shift on the fly button switch as well but you have 4lo or 4hi. That's it. You can shift on fly to 4 hi but have to stop put in nuetral with foot on brake for 4lo.

So what is the deal with the multimode?

 

[Stuck CAPS]

Speaking of, 4Runner 4x4 still has me baffled. (4) four wheel drive modes (4hi & lo unlocked)(4hi & lo locked).
I understand that only use the (locked) when off-road or low traction conditions but unlocked can still be used on dry conditions.....but how come?

I'm coming from Ford trucks that you have the shift on the fly button switch as well but you have 4lo or 4hi. That's it. You can shift on fly to 4 hi but have to stop put in nuetral with foot on brake for 4lo.

So what is the deal with the multimode?

The center diff lock is like a front or rear diff lock, in that it splits power 50/50 between the front/rear ends. In a differential lock, it's unwise to attempt to turn, because your diff gears will all spin at the same speed, and turning makes one side spin faster. In the center diff lock, when it's not being used for low-traction conditions, doesn't allow for a difference in power between front and rear diffs, which is required in in a lot of every day driving: mainly turning. Those drive shafts need to spin at different speeds to turn correctly, without extra stress on the drive train. This explains it pretty well. Courtesy [MENTION=2798]JB.[/MENTION]

It's much better to put in neutral still, because on the fly, if the gears aren't completely synced, it will typically make a slight grinding sound when shifted on the fly,which grinding from a shift, no matter the type of shift, isn't good. Just because you CAN do it, doesn't mean you SHOULD.

 

[CAN-03runner]

Speaking of, 4Runner 4x4 still has me baffled. (4) four wheel drive modes (4hi & lo unlocked)(4hi & lo locked).
I understand that only use the (locked) when off-road or low traction conditions but unlocked can still be used on dry conditions.....but how come?

I'm coming from Ford trucks that you have the shift on the fly button switch as well but you have 4lo or 4hi. That's it. You can shift on fly to 4 hi but have to stop put in nuetral with foot on brake for 4lo.

So what is the deal with the multimode?

Typical 4x4s have a transfercase and with reduction box and differential in the front and a differential in the rear. When the transfercase is engaged in 4x4 4hi it locks up the front and rear drive shafts and gives you 4x4. To get more torque you can engage the reduction box gears and engage 4low. This is another set of gears that provides more reduction (mechanical reduction) to generate more power to the wheels. You need to stop to do this. ( I think with some trucks you can do this while going really slow) Picture yourself trying to manually allign gears or a chain over a gear while everything is still spinning fast and then not have it grind when you do.

4th gen 4runner have a differential in the front and differentail in the rear, and also one in the center in addition to the transmission/transferace/reduction box and a button to activate 4x4. The 4hi knob and 4lo knob is to select which set of gears you will use, regular or reduction for 4lo. So you need to be stopped so the gears don't grind. But in simple 4hi or 4lo the center differential essentially makes your 4th gen an AWD truck which is why you can drive it in 4hi or 4lo on dry pavement and still make turns with no binding and it is not really in 4x4 until you lock that center differential, which you can do even while you are driving and even at a good highway speed. As long as there is snow, ice, sand etc... on the ground or you are going straight it should be fine.

It that center differential that makes the 4th gen 4runner different from almost all other 4x4s. :first: yea 4runner

 

[bagginz]

I don't know why it took me this long to figure out, but you can lock the center differential on the fly in 4high. I always thought I had to put it in 4low to lock it. I feel like a dummy but now that I know I can do this, wheeling around on the snow covered job site is easier and more fun! No more "granny mode."

I just found this out 2 days ago haha. Your not alone. Cheers!

 

[NasaE30]

Thanks OP I didnt know that either. I still have lots to learn about what The 4runner can do.

My problem is knowing exactly when to lock the center diff. I was climbing a step type rock obstacle at the top of a very steep climb. Wet.
I was in 4lo unlocked. Didnt make it, Tried locking, that just spun all 4, It just didnt feel right. So I unlocked, still in 4lo left foot braked, kept the rpms low and tried to tq over it. I finally made it with a little wheel spin but got over. Locking did Not seem to help.

So when should I use it? Yes, Yes. Every situation is different, but just a guideline would be helpful Thank you. :ear:

 

[JB.]

Thanks OP I didnt know that either. I still have lots to learn about what The 4runner can do.

My problem is knowing exactly when to lock the center diff. I was climbing a step type rock obstacle at the top of a very steep climb. Wet.
I was in 4lo unlocked. Didnt make it, Tried locking, that just spun all 4, It just didnt feel right. So I unlocked, still in 4lo left foot braked, kept the rpms low and tried to tq over it. I finally made it with a little wheel spin but got over. Locking did Not seem to help.

So when should I use it? Yes, Yes. Every situation is different, but just a guideline would be helpful Thank you. :ear:

Basically, use it off-road, that's it. Even if it didn't seem to help, for any difficult conditions off-road it should be locked.

But here's a little more detail.

4 hi
Center unlocked: Normal road conditions.
Center locked: Higher speed off-road or slippery conditions where unlocked may not be enough. Only in severe, short-term cases would you use this on road.

4 lo
Center unlocked: For use off-pavement or off of normal roadways where power and/or control is needed, and easier, more precise turning that doesn't scrub the tires or stress the drive train is desired.
Center locked: The toughest of slow speed, off-road conditions where you want/need the highest traction abilities.

 

[Martinjmpr]

Thanks OP I didnt know that either. I still have lots to learn about what The 4runner can do.

My problem is knowing exactly when to lock the center diff. I was climbing a step type rock obstacle at the top of a very steep climb. Wet.
I was in 4lo unlocked. Didnt make it, Tried locking, that just spun all 4, It just didnt feel right. So I unlocked, still in 4lo left foot braked, kept the rpms low and tried to tq over it. I finally made it with a little wheel spin but got over. Locking did Not seem to help.

My guess is that this happened because the VSC/TRAC was acting as a sort of half-assed locker or limited slip, preventing your wheels from slipping too much. Locking the center diff disables the VSC.

So when should I use it? Yes, Yes. Every situation is different, but just a guideline would be helpful Thank you. :ear:

On pavement you should never have a reason to use locked center diff. The only exception I can think of is deep snow. Keeping the center diff unlocked will allow the front and rear driveshafts to turn at different speeds which will prevent undue wear or damage to your drivetrain.

Off road I like to lock the center diff as soon as I am on dirt.

Basically, you can think of it like this: When your center diff is LOCKED, it is like you have an old-school 4x4, the kind where you can only use 4wd on a low traction surface. So when you are on the kind of terrain where you would put an old vehicle like that into 4wd, that's when the center diff should be locked.

When the center diff is UNLOCKED, it's like you have an AWD car like an Audi or a Subaru. So keep the center diff unlocked when you're on the highway or regular city streets (or keep it in 2wd if you have a V6.)

If you're on pavement with intermittent patches of ice or snow, you can put it in 4hi, Unlocked and, again, it's like you've got an AWD car. Then once you turn off the pavement onto a dirt trail, you can lock the center diff and it's like you have an old-school 4x4.

Does that make sense?

 

[Gecko123]

Straight from the Toyota 4Runner manual:

Use the four- wheel drive control switch
knob and center differential lock switch
to select the transfer and center differential
modes.
The “H4” and “L4” positions of the fourwheel
drive control switch knob provide
either lock or unlock mode of the center
differential depending on the center differential
lock switch position.
Use the center differential lock system if
your wheels get stuck in a ditch, or when
you are driving on a slippery or bumpy
surface. When the center differential is
locked, the vehicle stability control system
is automatically turned off and the center
differential lock and “VSC OFF” indicator
lights come on because the function that
controls engine performance interferes
with the process of freeing your wheels.
NOTICE
As soon as the center differential lock
switch is turned on, the “VSC OFF”
indicator light comes on. After the
wheels are out of the ditch or off the
slippery or bumpy surface, turn the
center differential lock switch off.
Make sure that the center differential
lock indicator light and vehicle stability
control system off indicator light
turn off.
“H4” (high speed position, center differential
unlocked): Four- wheel drive control
switch knob at “H4”, center differential
lock switch left out
Use this for normal driving on all types of
roads, from dry hard- surfaced roads to
wet, icy or snow- covered roads. This
position gives greater economy, quietest
ride, least wear and better vehicle control.
“H4” (high speed position, center differential
locked): Four- wheel drive control
switch knob at “H4”, center differential
lock switch pushed in
Use this for greater traction when you
experience a loss of power, such as
wheel slipping, in the center differential
unlock mode.
“L4” (low speed position, center differential
unlocked): Four- wheel drive control
switch knob at “L4”, center differential lock
switch left out
The “4LO” (low speed four- wheel drive)
indicator light comes on when the “L4”
mode is selected.
Use this for maximum power and traction.
Use this for climbing or descending steep
hills, off- road driving, and hard pulling in
sand or mud.
In this mode, the braking feeling that occurs
when the wheels are negotiating a
sharp corner is further reduced than in the
“L4” (low speed position, center differential
locked) mode.
“L4” (low speed position, center differential
locked): Four- wheel drive control
switch knob at “L4”, center differential lock
switch pushed in
The “4LO” (low speed four- wheel drive)
indicator light comes on when the “L4”
mode is selected.


Use this for maximum power and traction.
Use this for hard pulling in situations the
vehicle cannot negotiate even in the “L4”
(low speed position, center differential unlocked)
mode. Also, using this mode when
driving down steep off- road inclines will
help contribute to increased vehicle stability.
The indicator light tells when the differential
lock is engaged. Note that the differential
is not still locked as long as the
indicator light remains off.
When the operation is not completed, the
indicator blinks. If the indicator light does
not go off when you push out the center
differential lock switch, drive straight
ahead while accelerating or decelerating,
or drive in reverse.
If the center differential lock system operation
is not completed within 5 seconds
while the cruise control system is set,
cancel the cruise control system. To cancel
the cruise control system, see “Cruise
control” on page 195 in Section 1- 7.
If the indicator blinks even if doing so,
contact your Toyota dealer as soon as
possible. There may be a trouble in the
center differential lock system.
See “(b) Shifting procedure” for further instructions.
SHIFTING BETWEEN “H4” (UNLOCKED)
AND “H4” (LOCKED)
To shift between unlock and lock
modes in “H4”, push the center differential
lock switch.
SHIFTING BETWEEN “L4” (UNLOCKED)
AND “L4” (LOCKED)
To shift between unlock and lock
modes in “L4”, push the center differential
lock switch.
SHIFTING BETWEEN “H4” AND “L4”
To shift from “H4” to “L4”, bring the
vehicle to a complete stop with the brake
pedal held down with your foot, shift the
automatic transmission selector lever into
“N” and push and turn the four- wheel
drive control switch knob fully clockwise.
To shift from “L4” to “H4”, bring the
vehicle to a complete stop with the brake
pedal held down with your foot, shift the
automatic transmission selector lever into
“N” and turn the four- wheel drive control
switch knob fully counterclockwise.
If the “4LO” (low speed four- wheel drive)
indicator light continues to blink when you
operate the four- wheel drive control
switch knob to the “H4” or “L4” position,
drive forward or backward in a short distance,
then stop the vehicle completely,
shift the automatic transmission selector
lever securely into “N” and operate the
switch knob again.
If the indicator continues to blink even if
doing so, contact your Toyota dealer as
soon as possible. There may be a trouble
in the four- wheel drive system.
CAUTION
Never operate the four- wheel drive

 

[cloh09]

The center diff lock is like a front or rear diff lock, in that it splits power 50/50 between the front/rear ends. In a differential lock, it's unwise to attempt to turn, because your diff gears will all spin at the same speed, and turning makes one side spin faster. In the center diff lock, when it's not being used for low-traction conditions, doesn't allow for a difference in power between front and rear diffs, which is required in in a lot of every day driving: mainly turning. Those drive shafts need to spin at different speeds to turn correctly, without extra stress on the drive train. This explains it pretty well. Courtesy [MENTION=2798]JB.[/MENTION]

It's much better to put in neutral still, because on the fly, if the gears aren't completely synced, it will typically make a slight grinding sound when shifted on the fly,which grinding from a shift, no matter the type of shift, isn't good. Just because you CAN do it, doesn't mean you SHOULD.

I was really commenting on being able to lock the diff in 4high. It had never occurred to me.
Neutral probably is the best and safest way to lock it, but if you do lock it on the fly, you need to be going dead straight.

 

[Gdunc]

Limited has H4F, H4L and L4L. 4L locks diff or transfer case. Whatever you want to call it. AWD works great and can save your butt on slick curves. First wheel that slips it locks front wheels in. I like the A Trac best.

 

[Gdunc]

Limited edition is practically a Lexus.

 

[Flyer]

The center diff basically makes it part-time 4WD in a V8 4R. Otherwise it is AWD. It is not anywhere as good as a rear or front locker on top of being in 4WD.