whats the diff??

milo · Guru

whats the diff??

Peter_n_Margaret · Guru

A truck with 6 wheels on 3 axles might be 4 wheel drive or it might be 6 wheel drive (all wheel drive).

Cheers,
Peter

Firefly · Guru

Hi Milo, I looked this up for an easy explanation mate. Always confused me too. smile

Four wheel drive first:

http://en.wikipedia.org/wiki/Four-wheel_drive

All wheel drive:

http://en.wikipedia.org/wiki/Category:All_wheel_drive_vehicles

Gives lots of examples in that one.

I will get lost here now looking them all up. biggrin

blaze · Guru

most 4 wheel drives are only 2 wheel drive any way, one front and one back wheel, there are modifacations that can be done to make all wheels drive but they dont turn very well. I have a discovery and they call them a constant 4 wheel drive, the drive automaticly goes to the wheel that is slipping, one at the front an d one at the rear.
cheers
blaze

ozjohn · Guru

The way I understand it:

AWD (All Wheel Drive) that all the wheels constantly drive. You cannot selot btween 2 wheels and 4 wheels.

4WD or 4X4 (4 Wheel Drive) is where you can select either 2 wheel drive or 4 wheel drive.

Cheers, ozjohn.

Yuglamron · Guru

4x4 basically means there is an extra diff in the drivetrain.

A 'Normal' two wheel drive has a diff to allow one wheel to turn faster when cornering.

A 4x4 has an extra diff to drive the other axle.Same thing the outside wheel on a cornering car has to travel further than the inside one hence the need for a diff.

Most 4x4's have the extra diff to drive all four wheels.It also generally has an extra low range in the extra diff to drop the speed to make 4x4 driving slower and of course then gives extra grunt.

Then there are locking wheel hubs to help the four wheel drive(A lot of modern 4x4's have auto hubs)

Another aid is a lockable diff to make all the wheels turn together at the same speed.

All tools to aid 'Proper four wheel driving'

Hope this has not complicated it too much.

PeterD · Guru

WOW there are some confusing answers there.

Try this - 4WD is generally applied to vehicles that are run in 2WD on hard roads and you can engauge the front wheel drive when you are running on soft ground.The problem with this system is that when you turn corners the front axle tries to turn faster then the rear one. This is creates transmission wind up. If you run your vehicle on hard ground this wind up is likely to bugger your differentials.

AWD (all wheel drive) vehicles have both axles driven all the time. They have differential (or alternately a viscous coupling) between the front and rear drive sharfts to prevent transmission wind up.

milo · Guru

thanks all for trying to explaine all this