does the 4x4 gearbox foul the chassis anywhere??

also is it a permanent split between front / rear? if it is can i blank off the output to the front so as to only run rear wheel drive?

then i can upgrade to 4wd at a later date without having to drop the engine /gearbox out

Hello,

It'd probably fit in a standard chassis - you just have a bulge in the drivers footwell under your knee where the output to the front diff is. But if you were making the car with 4WD in mind you might have to move the engine and gearbox back to give room for the front axle - possibly not if you used a V6. This would involve widening the transmission tunnel a bit.

The torque split is 1/3 to the front and 2/3 to the rear (under no slip). Yes theoretically you could simply not use the output to the front - the centre diff would think the front wheels are slipping and lock up transfering all the power to the rear. In practice though the centre diff viscous coupling can't lock 100% (more like 80%) and so you would always waste some of the power. I think you would also experience lower gearing cos the rear output of the centre diff will be spinning slower than the input from the gearbox whilst the unused front output will spin faster (if the centre diff works like a conventional one). I doubt the viscous coupling of the centre diff would like running constantly locked either - but I dunno.

I have a spare 4x4 box that I keep offering to people - you're welcome to have it for measuring up or whatever. If you're getting a 4x4 Sierra donor you could disconnect the front prop and see how long this RWD only scheme takes to destroy a centre diff (if ever) and you'd have a spare.

Liam

By the way - about fitting in a standard chassis - Ewan is the man to ask. I just remembered (I think) he built a standard chassis and modified it to take the 4x4 gubbins.