GrumpyGel
Well-Known Member
But Freelander isn't RWD, nore is it a plane or a train - you are not comparing similar things.
So you know what a diff does? The rear diff distributes power between the rear wheels - a solid axle with no differential would not allow the car to go round corners. The same with a front diff on a front wheel drive car. On a 4WD or (as the case with Freelander) AWD both axles are driven and both have differentials - but if you lock the 2 axles together with a solid prop (gearing) then you have the same problem - you need something to separate the axles some way.
On a 4WD car you have a lever to a gear that switches between 2 and 4 wheel drive - when driving on road you would always be running 2WD (usually RWD) - its only when you get onto slippery stuff you engage 4WD. If you had 4WD engaged on road it wouldn't go round corners.
On a Permanent 4WD car (like Defender & Discovery) you have a center differential that distributes power to both axles in exactly the same way a diff in the rear axle distributes power to the 2 back wheels. This way the car is always running 4WD.
With AWD cars you traditionally have a Viscous Coupling that disengages the back axle when all is good - so its running essentially FWD most of the time. But when the front wheels slip it locks up to drive the rear wheels.
What you are proposing is turning the AWD Freelander into a 4WD car without the ability to run 2WD - so you wouldn't be able to go round corners - you would have windup - that is what windup is (as well as other bits like big or small differences in tyre sizes).
So you know what a diff does? The rear diff distributes power between the rear wheels - a solid axle with no differential would not allow the car to go round corners. The same with a front diff on a front wheel drive car. On a 4WD or (as the case with Freelander) AWD both axles are driven and both have differentials - but if you lock the 2 axles together with a solid prop (gearing) then you have the same problem - you need something to separate the axles some way.
On a 4WD car you have a lever to a gear that switches between 2 and 4 wheel drive - when driving on road you would always be running 2WD (usually RWD) - its only when you get onto slippery stuff you engage 4WD. If you had 4WD engaged on road it wouldn't go round corners.
On a Permanent 4WD car (like Defender & Discovery) you have a center differential that distributes power to both axles in exactly the same way a diff in the rear axle distributes power to the 2 back wheels. This way the car is always running 4WD.
With AWD cars you traditionally have a Viscous Coupling that disengages the back axle when all is good - so its running essentially FWD most of the time. But when the front wheels slip it locks up to drive the rear wheels.
What you are proposing is turning the AWD Freelander into a 4WD car without the ability to run 2WD - so you wouldn't be able to go round corners - you would have windup - that is what windup is (as well as other bits like big or small differences in tyre sizes).
Nodge68
Well-Known Member
Absolutely. Why not just replace the front and rear diffs with solid shafts too. Then it'll be a true 4WD. Sadly it would blow half shafts and drive splines in very short order.
There's a rule that I go by. If it ain't broke, don't fix it
SpringDon
Well-Known Member
Ooo, I think I see what you did there.
GrumpyGel
Well-Known Member
Be fair to the guy, he's probably just sacrificed 6 hard long weeks studying for an NVQ in Advanced Motor Engineering that he's passed with flying colours and putting what he's learnt to use.
Probably just needs his pimples to dry up, his Landie to break down and a couple of sessions at the LZ school of hard knocks for him to find out some basics on how cars work.
Probably just needs his pimples to dry up, his Landie to break down and a couple of sessions at the LZ school of hard knocks for him to find out some basics on how cars work.
FlyingPete
Well-Known Member
The Freelander is basically front-wheel drive, with a power take-off driving the rear axle. The VCU allows the front and rear wheels to turn at different speeds while cornering, which they need to do. Part-time 4wd vehicles achieve the same by disconnecting the drive to one axle (reverting to 2wd) and permanent 4wd vehicles use a central diff to split the drive between front and rear. You need one of the three methods to use the vehicle on the road.
You could replace it with a dog-clutch of some sort, giving you a selectable system. Or remove it and have a 2wd car. But you can't just get rid of it and have a solid drive shaft. If you could, it's what Land Rover would most likely have done in the first place.
You could replace it with a dog-clutch of some sort, giving you a selectable system. Or remove it and have a 2wd car. But you can't just get rid of it and have a solid drive shaft. If you could, it's what Land Rover would most likely have done in the first place.
Nodge68
Well-Known Member
The front and rear drive ratios are different which discounts any form of solid connection, dog clutch or otherwise. The system was designed to use the VCU and nothing else
lenny1234
Active Member
The front and rear drive ratios are different which discounts any form of solid connection, dog clutch or otherwise. The system was designed to use the VCU and nothing else
Ah . That must be why I have to change the VCU every 30 miles then, its been deliberately designed to be under severe slip at all times...
Sometimes I do wonder at some of the rubbish people talk about VCUs and transmissions.
GrumpyGel
Well-Known Member
Who said anything about it being designed to be under severe slip at all times? The fact is that there is a gearing difference which you would find out immediately if you replace the props & VCU with a solid connection. Also fact that the VCU allows this gearing difference to operate without screwing itself up, for maybe up to 150K miles - but usually less.
Sometimes I do wonder at some of the rubbish people talk about VCUs and transmissions.
guineafowl21
Well-Known Member
You are thinking of a 4WD car, whereas the Freelander is an AWD - it HAS to have a VCU fitted. The VCU system actually works quite well, as long as you look after it, and a recon/exchange replacement unit only costs £200 or so. If you're after better off-road performance put some mud tyres on and lift it 2".
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