So how does this four wheel drive work then ??

[V6Jon]

Something has been running through my brain for a few days, and I am hoping you terribly clever types can help

In normal driving a Fronty engine turns the gearbox, which turns the transfer box, which turns the rear diff, which turns the rear wheels, agreed ?

And the rear diff allows the inner and outer wheels to turn at different speeds.

With me so far ?

When I switch to four wheel drive, the above continues to happen, but the transfer box also directs drive forward to the front diff which turns the front wheels, so my questions are :

Does the front diff allow the inner and outer front wheels to turn at different speeds ? I presume yes

Does the transfer box allow the front and rear diffs to turn at different speeds ? I presume no

I was just wondering where the problem lies with driving on tarmac in 4wd, I presume the front diff allows the front wheels to turn independently, so the issue is with the lack of a centre diff ??


or should I direct my barking at an entirely different connifer ??

Any help gratefully received, as I like to know how things work and if you lot dont tell me, I will have to take it all apart and work it our for myself

Cheers guys

[headbanging]

[V6Jon]

That was my understanding, but as there are diffs front and rear, those pairs of wheels should be able to turn at different speeds.

This made me think that the problem was that the transfer box does not allow the front and rear diffs to turn at different speeds ?

when a car turns a corner, the front wheels describe a much larger arc then the rear, especially at full lock !

Jon

[gregster]

Hiya mate....

You are quite correct...a frontera and in fact most Jap 4x4's do not have a centre diff as such. When 4x4 is engaged the front prop can only turn at the same speed as the rear. The axle diffs take care of differences in wheel speed on each axle, but with the locked centre diff type set up we have got, there is no ability to be able to deal with wheel speed differences from front to rear.
So, as you say, if you drive in a tight circle and the front takes a wider line whilst in 4x4, then the tyre with least traction will slide to loose this difference. However if used in 4x4 on a hard grippy surface this can cause the car to bind up as it is difficult for a tyre to slip, which could result in drive train damage.

Landrovers have an open centre diff as are permanent 4x4, with a selectable diff lock in the transfer box for the centre diff...This means that they can use 4x4 on a hard surface without bind-up, the centre diff lock being neccesary if climbing hills etc, where other wise the drive would go to the axle of less resistance (and the front 2 tyres would spin, with no drive to the rear)...diff lock then locks front to rear like on our fronties so equal drive is shared betweenn front and rear axles...

4x4 on a fronty should only be used on loose surfaces where traction is limited, so that a wheel can slip easily if required to loose the difference in front/rear axle speed.

I choose to fit manual locking hubs to my 4x4's so that I can leave these unlocked, and then utilise low range in 2wd for shunting trailers on hard surfaces...saves the clutch a bit as speed is slower off the clutch..

hope this helps

Gregster

[V6Jon]

Thanks Gregster, that was what I thought was going on.

I suppose the upside to the fronty system is that when off road we effectively have a permanently locked centre diff, so as long as one axle has grip you aren't stuck.

If only they had been built with LSD's or lockable front/rear diffs Fronty's would be unstopable !!


Jon

[gregster]

Isuzu's will the G88 option code had LSD rear...and the axles fit a fronty!

Also ARB's, detriots and ausi lockers are available for the isuzu axles...

My chevybravafing has rear LSD

[V6Jon]

Had heard about the Isuzu axles, but didn't know about about the lockers availiable.

Not something I would do my my current fronty as it is my daily driver, and wont see much mud.

But I have planted the idea in the bosses brain that a swb base would make a nice plaything, so when a suitable one comes up that I can afford it will be getting steel bumpers, suspension lift, body lift, big wheels / tyres and lockers

[Drift]

LSD explained

http://en.wikipedia.org/wiki/Limited_slip_differential

http://auto.howstuffworks.com/search.ph ... fferential

And 4WD Fronty style.

http://www.fronteraowners.co.uk/wiki/in ... _FAQ/Guide