[svsantosh]

all 4WD/AWD on one page - a simple, easy to understand overview - all available 4WD, all wheel drive and 4x4 systems and their differences - 4WD concepts, their function, their layout, their purpose, their advantages

I got this from the thread 'lamba free wheeling hubs'.

Which among these in INDIA are part time/ full time 4WD, The Mahindra Major, The Gypsy, or the safari 2.2 4x4, Scorpio 4x4 electric, bolero LX 4x4, bolero SX electric 4x4, mahindra rakshak, mahindra axe, Force Gurkha?, etc etc.

[GTO]

Which among these in INDIA are part time/ full time 4WD, The Mahindra Major, The Gypsy, or the safari 2.2 4x4, Scorpio 4x4 electric, bolero LX 4x4, bolero SX electric 4x4, mahindra rakshak, mahindra axe, Force Gurkha?, etc etc.

Not sure about the Mahindra AXE, but the rest are all part-time 4WD. You have to engage the fronts (mostly) manually.

[Alfa_Kilo]

They are all part time 4x4s. Some versions of the Axe may have a central diff making them full time 4x4.

[Blue Thunder]

Originally Posted by Alfa_Kilo

They are all part time 4x4s. Some versions of the Axe may have a central diff making them full time 4x4.

Just the provision of a center differential doesnt make it full-time 4x4. For a vehicle to be called full-time 4x4, there should be no provision to shift to 2WD : there may be a gear-lever for shifting between 4H and 4L, but no possibility to shift to 2WD. There definitely will be a center differential.

[Samurai]

I think Grand Vitara is the only full-time 4x4 in India. The CRV is automatic 4x4, the 4WD kicks when the need is sensed.

[SirAlec]

wat about tucson, terracan, mercedes M?

[Samurai]

Originally Posted by SirAlec

wat about tucson, terracan, mercedes M?

Tucson is automatic 4WD (otherwise FWD), and Terracan is part-time.

[sbasak]

For a vehicle to be called full-time 4x4, there should be no provision to shift to 2WD

Usually having a central differential means no provision of 2WD. Also, all cars which have a central diff, have diff locks.

I may be wrong, but most likely Toyota Land Cruiser (Prado) has central diff.

[4x4addict]

Originally Posted by Blue Thunder

Just the provision of a center differential doesnt make it full-time 4x4. For a vehicle to be called full-time 4x4, there should be no provision to shift to 2WD : there may be a gear-lever for shifting between 4H and 4L, but no possibility to shift to 2WD. There definitely will be a center differential.

Some full-time 4x4 systems allow you to be in 2WD to improve FE. One example of this is the Pajero Super Select 4x4 systems. They can be driven in full time 4x4 or in two wheel mode. Driving it in full time four-wheel drive mode doesn't hurt the vehicle in anyway since all three differentials are open. So you don't care about FE, you can always leave it in Full-time 4x4 (awd) mode and apart from the drop in FE there are no other issues..

Samuri:

My understanding of the Suzukui 4x4 system is that it is the same Borg Warner Torque on Demand system that came on the Isuzu Trooper (also owned by GM). This system has the same center diff like the Land Cruiser or Pajero, but sensors will enable torque to the front wheels only if slippage is detected. But of course you can lock the center diff if needed.

Originally Posted by sbasak

I may be wrong, but most likely Toyota Land Cruiser (Prado) has central diff.

This is true most of the time for exampl ein the Land Cruiser AWD system. But some cases you can do it manually like in the Mitsu Super Select System or automatically like the Borg Warner TOD system employed in the Isuzu Trooper and GV (Need to confirm this)

[Sankar]

Originally Posted by Samurai

I think Grand Vitara is the only full-time 4x4 in India. The CRV is automatic 4x4, the 4WD kicks when the need is sensed.

Chevrolet (Subaru) Forester. That is one excellent vehicle with a full time 4WD system. Sadly it's not being sold anymore, the pricing was too wrong. The spares were horribly expensive. But the handling was just beautiful with fulltime 4WD!!

[nitrous]

The forrester is an estate with AWD.
Not an off-roader!

[Samurai]

Originally Posted by 4x4addict

My understanding of the Suzukui 4x4 system is that it is the same Borg Warner Torque on Demand system that came on the Isuzu Trooper (also owned by GM). This system has the same center diff like the Land Cruiser or Pajero, but sensors will enable torque to the front wheels only if slippage is detected. But of course you can lock the center diff if needed.

Nope, not on GV. It has central diff with LSD, which can be locked.

[Blue Thunder]

Originally Posted by 4x4addict

Some full-time 4x4 systems allow you to be in 2WD to improve FE.

Then it cannot be called a full-time 4X4 . This is a part-time 4x4 which has a center differential.

As I said earlier, full-time 4x4 means there should be no provision to shift to 2WD.

[Sankar]

Originally Posted by nitrous

The forrester is an estate with AWD.
Not an off-roader!

Forester is a softroader like the Honda CRV and it's build on the Impreza platform like the CRV is built on the Civic platform.

It's not an estate. Subaru Legacy is the estate version build on the Impreza platform.

[turboglx]

I have quoted text below from a 4X4 site:

"What is the difference between Full time Four Wheel Drive (4WD) All Wheel Drive (AWD) and automatic All Wheel Drive (auto AWD)?


Full time 4WD, also called permanent 4WD, (not to be confused with: part time 4WD ) is a system that powers all four wheels at all times and can be used full time on all surfaces including pavement. The additional feature of a differential incorporated into the transfer case makes it possible to use 4WD all the time.
2WD is not available (only part time 4WD offers that option). Each tire creates about 25% of the available torque when the ground is level with a consistant surface. Driver has a choice of a "4-high" (that's your every day setting) and "4-low".
Full time 4WD vehicles work very well on-road and are very capable off-road.

When "4-low" is selected the wheels create substantially more torque (on a Grand Cherokee its 2.72 times more) than in "4-high" - at the same time the vehicle moves at substantially slower speeds (2.72 times slower on a Jeep Grand Cherokee).

Important: "4-low" does not create more traction - it creates more torque and that can be detrimental when traction is marginal. Slipping tires are more likely in "low" than in "high"!

The low setting is an advantage for drivers who need to tow and maneuver a heavy trailer etc. and for drivers who at one point or another may want to negotiate difficult off-road terrain, when more torque and/or slower speed is needed.

All wheel drive (AWD) is almost the same thing as full time 4WD - it is a system that powers all four wheels of a vehicle at all times as well. Full time symmetric AWD would be the best term to be used. Difference to full time 4WD is that a "4-low" setting is not available in AWD cars. Due to the lack of "low range" AWD vehicles are much less capable in off-road settings than full time 4WD vehicles, but work perfectly well on-road.

Automatic AWD system is the newest kid on the block. PR agency generated names like "Real Time 4WD", "intelligent AWD" or "active AWD" are hiding the fact that automatic AWD is essentially a sophisticated 2WD system. Automatic asymmetric AWD would be the best term for them.

Here is how they work: Under normal conditions one axle gets 100% of the torque - meaning you are driving in 2WD. During traction loss at the driven axle (could be front or rear) a fully automatic system (hydraulic, mechanical or electronic) makes up to 50% of the torque to the axle with traction available. This means you have to lose traction in 2WD on your driven axle first and then the other axle will be added and try to keep the car moving and stable. Once the primary driven axle regains traction and both axles rotate at the same speed again, the system reverts back to 2WD. So, for a moment you had AWD.

Automatic asymmetric AWD is much less capable in off-road settings than full time AWD systems and inferior to full time 4WD. However, automatic asymmetrical AWD is becoming more and more sophisticated and offers pretty much everything consumers expect for everyday (pavement) driving.

Examples: Honda CRV, (newer) Toyota RAV4, LandRover Freelander, Isuzu Trooper (TOD), Volvo V70, 1999 and later Jeep Grand Cherokee (in high range).

Recently some magazines have called the automatic AWD system "part time 4WD", since it offers AWD only part of the time. They have a point - however, the term "part time 4WD" has been used since WW II for cars like the Willys and Jeep Wrangler and their part time 4WD . A manual system where the driver had to select 2WD or 4WD. The name coming from the fact that 4WD was designed to be used only part of the time (when off-road), most of the time it had to operated in 2WD (on-road)."

I hope this helps.

A quick note, the Toyota Prado is fulltime 4WD with a locking centre diff, the Toyota Landcruiser (80 series and some variants of the 100 series) are fulltime 4WD with 3 locking diffs.(front, rear, center)