I've found a million pictures on google and looked at it for ages, but can't quite twig on how it works. Can anyone explain with a picture they have or a simplified diagram?

 

Try this one. Looks more complicated than it actually is principle because of the way it's packaged.



OK, should point out that is one concentrates more on the transfer box.

The centre diff is a 'proper' differential, there is drive from the gearbox to the diff carrier, providing 2 drive outputs via the side gears, one drives the transfer to the rear, the other drives the front diff which is embedded in the transfer box.

In layout terms I think the positions of the front & centre diffs are swapped compared to something like the MTX75 4x4 gearbox - the latter doesn't really have a centre diff in the same sense.

The hydraulic clutchpack to control the centre diff is at the RH side of the diagram & remote from the actual differential. Normally the diff is fully open, in theory you could drive it to 100% locked but the clutch plates wouldn't like it. Torque split is 50/50, variable split comes from locking the diff to different amounts to try to force the axles to rotate at the same speed, depending on surface & direction of travel the axles may be at different speeds for equal torque (for open diff), trying to equalise the speeds forces a change in torque to the axles.

Bear in mind that unlike a lot of 4x4 boxes this one won't normally allow easy 2wd operation as it doesn't have a permanent link from gearbox to either front or rear axles.

 

Thats wicked! thanx a lot! Scooby setup is a lot simpler!! lol