Prado constant drive

Not sure of various Hiluxes Razerback but I think they are the same as some Patrols.

You can use the Patrols 4wd on any slippery surface like wet bitumen and they work real well, so often I see cars take off and spin the back wheels when wet and because the Patrol can go in/out of 4wd on the run in high range its a breeze to take off in 4wd and flick back to 2wd after you have left the 2wd car standing.

In practise the Prados get left behind to because they are almost always in AWD mode such that when 1 wheel spins their down.
Doesn't need to be this way because they can lock centre diff of course but in practise they don't around town.

The above works because all except base model Patrols have auto engaging front hubs (love it) and serious LSD.

BTW - 4WD should not be used on the bitumen. You will get diff wind up and this will damage your drive train.

Yours must be different to my 2008 GXL D4D auot then, the automatic transmission unit is full time all wheel, it has a center diff as well as the usual front and rear differential same as written above.

Vehicle normally drives all four wheels through the center diff, you can use the high low range in this mode, good for parking van.

When venturing off road you press the center diff look and vehicle and car is then basically the same as a part time 4X4, if you don't have locking hubs on the front wheels your vehicle is as above.

You are quite right. I didn't realise that - misunderstood meaning of Full-time 4x4 and Part-time 4x4. Confused following undertaking driver training in February.

You drive around town with High Locked selected?

In a full time 4wd you do not need front and rear diff locks for it to be like a normal 4wd - when the centre diff lock (not a front or rear diff lock) is locked it is the same as a part time 4wd when in 4wd.

Garry

Actually what you have written is not quite right, in the Toyota's with constant four wheel drive if any wheel loses traction, ie you lift one wheel of the ground the other wheels will receive little drive, ie back left wheel of the ground, the center diff will spin same as it would for a normal diff and drive the rear diff as the right wheel is off the ground that wheel will spin and the car will go nowhere, locking the center diff will send power to both front and back and if front wheels have traction vehicle will move forward, if a front wheel is off the ground the car still will not move.

That's the simplistic explanation, as most will have limited slip diff in the rear there will still be some drive still with these vehicles in all wheel mode with a rear wheel only off the ground if the center diff is locked and one front wheel is off the ground.

With the units that have traction control, the traction control will stop the wheel/s that are spinning by apply the brake on that wheel/s and the vehicle will have send drive to the wheels with traction in either constant 4x4 or with center diff locked.

When the center diff is locked the vehicle is classed as a part time 4X4 ie the same as the old original 4x4's except you don't have manual or auto hub locks on the front as there not needed.

Lockers are not required for the vehicle to be classed a true 4x4, most would say if you have a transfer case and high and low ranges you have a true 4x4 such as the first Toyota 4x4 had, lockers do not make a true 4x4 as you call it though as with limited slip diffs or traction control etc, as in the modern 4x4 they are nice to have if you need them and can afford them.

Cheers
Leigh

WTF?

Lockers do make it a true 4x4, you have solid drive to all 4 wheels. High/Low range changes your gear ratio not the drive(power) to all 4 wheels.
Slip diffs are exactly that, they slip, which means power goes to the wheel in that diff that has the least amount of resistance.
Lockers actually lock both wheels in the diff where fitted and drive the exact same revolution.
Centre diff lock does not do this, it locks in sync front and rear diff not all 4 wheels.
Diff wind up happens when centre diff lock and lockers engaged on hard surfaces.
So why not does it happen with a slip diff with or without centre diff lock?????????????????
Because its not a true 4wd drive!
Mate, get your facts right!

Part time 4wd means front diff is completely free wheeling (no drive) like a rear driven 2 wheel drive, even a 2 wheel drive is not, power is still going to one wheel.

HKB Electronics posted:
Actually what you have written is not quite right, in the Toyota's with constant four wheel drive if any wheel loses traction, ie you lift one wheel of the ground the other wheels will receive little drive, ie back left wheel of the ground, the center diff will spin same as it would for a normal diff and drive the rear diff as the right wheel is off the ground that wheel will spin and the car will go nowhere, locking the center diff will send power to both front and back and if front wheels have traction vehicle will move forward, if a front wheel is off the ground the car still will not move.

Ummmmm, what you have written is basically the same as what I wrote, except for one thing, when centre diff lock is engaged and you lose traction to one wheel, lets say at the rear diff, you still have drive at the front diff if both these wheels have the same traction.

Have you owned a 80 series?

Ummmm as you wrote that's what I wrote.

Four wheel drive simply means 4 wheels are normally driven, no distinction to under conditions, a constant 4 wheel drive is four wheel drive as long as 4 wheels are on the ground.

Others will say without a transfer case in is not a true 4 wheel drive others will say without a high long range capability it is not a true 4 wheel drive vehicle.

If you were to look at a car with lockers then you can also argue that it is not a functional 4 wheel drive vehicle as with the lockers locked it can't turn a corner!

The OP stated the Prado was not a fully capable 4 wheel drive vehicle, as it was constant 4 wheel drive, with the center diff locked it meets the common definition of what is accepted as an all wheel drive vehicle, ie all wheels are normally driven, it does need to have lockers to be called an all wheel drive.

Cruiser 61 - You did say that you needed front and rear diff locks to turn a constant 4wd into a 4wd. Now this is blatantly incorrect and I think you meant to say that a constant 4wd needs a center diff lock to make it a "proper" 4wd.

A constant 4wd like the GXL 80 series with the CDL locked is the same as say a 60 series with hubs locked and in 4wd. Front and rear diff locks adds an extra level of capability off road that applies equally to a part time 4wd that is in 4wd and a constant 4wd with cdl locked.

HKB - I appreciate you said others said you need low range to have a proper 4wd - well this is not true - it depends on the design of the vehicle. I have a 5 speed single range part time 4wd with 22" tyres and it is a far more capable 4wd off road than just about most other 4wds.

Garry

Garry,

I agree, as long as 4 wheels are being driven it is a 4 wheel drive vehicle, if it had 6 wheels being driven then it would be a 6 wheel drive vehicle.

Lockers don't necessarily make a 4 wheel drive vehicle more capable, I have seen well setup two wheel drive vehicles go to places a 4X4 with an unskilled driver couldn't get to.

Lockers can make a difference but in most cases I have seen they are simply being used to make up for lack of skill on the drivers part and a poorly setup up vehicle, wrong tyres and tyre pressures etc.

I remember watching an old black and white movie a while back of a very old two wheel drive vehicle about the size of a t model being driven in outback Australia many many moons ago, it successfully traversed roads with only skinny carriage type wheels that I doubt most modern 4X4's with or with out diff locks would have got through!

I have two vehicles, my Prado and a early KIA Sportage, the KIA can get up hills especially in slippery conditions in high range the Prado can't get up in low range, being lighter is better than both low range and diff lockers!

Cheers
Leigh

I Love these comments, "Lockers can make a difference but in most cases I have seen they are simply being used to make up for lack of skill on the drivers part and a poorly setup up vehicle, wrong tyres and tyre pressures etc."

Sadly the vehicle I bought came with factory lockers installed, may be I should have them removed before delivery.

Anyway, I am glad I didn't buy a Prado, because from what I have read on this forum, I really don't think I would be smart enough to put it into four wheel something.

HKB. I have seen that clip, and have been searching for it ever since, I reckon it is a classic.

Cheers

It seems we have an issue with what we are calling drive.

With a conventional diff the drive shaft drives the ring gear in the diff, if both wheels are on the ground both wheels will be driven not one. The spider gears in the diff will share the torque between the two wheels not one in the front diff and one in the rear diff as you put it.

If one wheel loses traction all the torque does not go to that wheel, the wheel spinning prevents torque being applied to the other wheels due to the spider gears doing what they do therefore the power is effectively lost, which is what happens with the center diff unlocked and one wheel slipping the cars stays put assuming no limited slip diffs
or traction control.

With the center locked power is sent to both the front and rear diffs,
same as above except we have taken the center diff action out, ie both drive shafts are locked together, therefore now if a front wheel looses grip, power is still available to the two rear wheels, if one of them loses grip we don't go anywhere again.

Center diff lock on, lockers on, power is sent to front and rear diffs,
torque is available to all wheels, it is not equal drive to all four wheels, if only one wheel has traction all the torque can effectively be transferred to that wheel, it is only equal drive as you call it if all 4 wheels are on the ground and have equal traction, if two are on the ground than they will get 50% each, one on the ground a 100%

Part time 4 wheel drive, drive is sent to rear diff only, both wheels driven as long as they are on the ground. Front diff maybe free
wheeling, depends if the hubs are locked or unlocked, they can be left locked but most will unlock them to reduce front diff wear, some part time 4x4's have auto locking hubs that engage when 4 wheel drive is selected.

The center diff is required to prevent transmission wind up and allow constant 4 wheel drive.

Sorry, part time four wheel drive above, I should have written when transfer case is not locked.

Part time 4X4 setup is exactly the same as what i have written for when center diff is locked

There isn't any transferring of torque between wheels on a locked diff. Effectively the axle is solid when the diff is locked so both wheels are turning at the same rate with the same power whether they have traction or not. Maybe I didn't understand how you said it?

HKB quote,
"Center diff lock on, lockers on, power is sent to front and rear diffs,
torque is available to all wheels, it is not equal drive to all four wheels, if only one wheel has traction all the torque can effectively be transferred to that wheel, it is only equal drive as you call it if all 4 wheels are on the ground and have equal traction, if two are on the ground than they will get 50% each, one on the ground a 100%"



I'm don't think you understand the concept of F&R lockers.

People get confused with terms such such as transfer of power, there is no transfer of power in a locked diff, as mikehzz wrote, the axle is locked both wheels are driven, transfer of power means if a wheels is sensed to be slipping then the power is removed from that wheel and sent to the one with traction.

It really is in the way you look at it, for instance the car is being driven with the diff lockers on and center diff locked, we therefore assume 25% of the available torque is going to each wheel. if one wheel was to loose traction each of the remaining wheels would have 33.3% of the torque available to them, there is no actual mechanical transfer of power, we haven't removed torque from the slipping wheel the slipping wheel still has the drive torque available it just can't lay it on the road.

A vehicle with locked center diff and traction control can work just as wheel as a locked diff, the traction control will brake the wheel that is spinning therefore the torque can effectively be applied to the other wheel, where not actually transferring the torque where just allowing the available torque that is there to be applied to the wheel with traction by stopping the other wheel spinning.

Very amusing, just like your post...................which has no relevance to the thread what so ever does it Phil the Dill.

Mick short answer no, the center diff lock does just that, locks the center diff and the vehicle is acts the same as a conventional part time 4X4 with a transfer case and locking hubs.

I think all the Prado's have a limited slip diff so you will still get some drive from the other rear wheel if one is spinning, though there is some doubt as to how good and how long the Toyota limited slip diffs last for.

If you get a unit with traction control it will act like a persudo lockers but with constant use then brake unit will overheat and turn off the traction control function.

I wouldn't be to worried about lockers unless your going to be doing extreme off road, I opted for a winches instead and haven't had to use them yet either, but then I don't abuse my vehicle. I look at the obstacle and decide if it looks like I'll damage my vehicle or it's to hard, if it is I'll try and find away around. If your a weekend warrior and a tow is available then it's not so bad, me I'm probably going to be hundreds of clicks from help so not going to risk damaging the vehicle if I can.

Forgot to add, the constant 4 wheel drive is great on wet and slipper roads when your not off roading, your spreading the drive over 4 wheels and I have yet to have a wheel spin on wet and greasy roads. I general leave mine with the center diff lock of on gravel and dirt also, I only tend to lock the center diff on step climbs and descent, or when rock crawling.

We have had ARB front and rear lair lockers installed 18 months ago purely because our 75 year young mother wanted to experience 4wding in the Flinders Ranges with us. I have to say the lockers are fantastic, more control over vehicle, take challenges at slower speed reducing the stress on vehicle which makes a more comfortable ride.
I should of installed them years ago.

There are few vehicles that come with axle diff locks as standard - some may have it as an option but for most it is an expensive aftermarket fitment. Many 4wds like some 2wds will have a limited slip diff in the rear as standard.

It is a shame discussion of axle diff locks came into the discussion so early in the thread as they are not really relevant to you original post and clearly have just muddied the information.

To answer your question above though - assuming all other aspects were equal, a $50K Pajero in full 4wd with a rear diff lock would most likely be superior in sand than the Prado with only centre diff lock. The same as a Prado/Nissan,Triton, Rover, Colorado etc would also be more capable if they also had a rear diff lock fitted.

I thought most Toyota 4wds already had a rear LSD as standard and was an option from Toyota. Neither wuld cause issues and if you got aftermarket is unlikely to mess up Toyota warranty.

But as said before the talk of axle diff locks has muddied the waters and unless you are looking at hi end 4wding with a high degree of difficulty I would question the need to install axle diff locks even in sand (some say they may be a handicap in sand but I don't believe so).

Garry