Originally Posted by Jono
Is that true? As a Land Rover Experience instructor...how much do they teach you about vehicles?
It isn't true if you are talking about all 4x4s not just LR.
All (I think! in case somebody can think of one with hydraulic wheel motors or something...) will have a front and rear axle diff but not all have a centre diff.
Old Series Land Rovers for example, and many others with "selectable" 4WD i.e. with a 2WD mode (1990s Mitsub L200 for example) don't have a centre diff, when you engage 4WD the drive is "solid" basically the same as if the centre diff is locked on a vehicle which has a centre diff. Suzuki Jimnys are the same, as are the old Suzuki Samurais, and some current Ford models (Everest and Ranger). Some vehicles have auto-disengaging front hubs but this is just to stop all the front drivetrain (diff, propshaft etc) spinning when you are in 2WD - in theory to reduce frictional losses and save some fuel, though whether it does is probably debatable.
Freelanders have a viscous coupling to the back axle which stiffens up if the front wheels start to slip and drives to the rear.
Freelander 2s have a complicated system in their rear diff called a Haldex diff which I don't fully understand but I think in the way it works its a complicated equivalent to the visc coupling on the old Freelander.
As Nasher said, on the Shoguns its recommended to use 4WD for towing, otherwise you are putting all the grunt through the rear diff and 4WD spreads the load. No idea what the "new" Shoguns have got though (the ugly 3.2L ones) as I have never really looked at those, but I think they are permanent 4WD.
Jap spec Pajeros don't have a rear diff lock.
Personally I like the Land Rover system, simple and it always works, which is more than you can say for traction control electronics, on the Freelander 2 launch here the journos had one vehicle crossaxled in a ditch and one of the LR guys said "it should drive out of there with Terrain Response" - "well it isn't..." out with the rope
it does work well but is not as dependable as proper axle difflocks which is why that is what my Defender will be getting when I stop pouring money into the hypalon industry