QUOTE >>>>Now, I'd been assuming that if the main box was in N, your transfer box wouldn't be connected through to the engine. Still, it ain't that important so forget it - I'm only trying to find out as much as possible coz I think mine's gonna break at some point.

Thanks and please continue to have patience, I'm sure you guys have helped me out on occasions in the past and it is appreciated. <<< unquote

It is ABSOLUTELY VITAL to see why being IN or OUT of gear affects the behaviour of the centre differential.

It doesn't matter which "neutral" is involved - the crucial point is to know whether or not the centre diff cage is held stationary (prevented from turning) by being connected solid drive through the transfer gears, the main gearbox, and the clutch, right through to the engine.

In ANY neutral, the centre diff cage is free to rotate, and WILL do so at TWICE the speed of the turning prop-shaft IF (a) the other propshaft is stopped from turning because its wheels are on the ground and (b) the centre diff is NOT locked.

This is THE point to grasp.

In ANY neutral, if one axle's wheels are on the ground, and the centre diff IS LOCKED, you will not be able to rotate either propshaft because BOTH are stopped from turning by the axle with wheels on the ground.

CharlesY