Yep this is it - on power the gear is locked - the front one way can only act like it does, as there are two independent drive shafts going into it. In the case of the centre oneway, a solid axle is placed through the gear. The front wheel can only therefore freewheel when they are rotating faster than the driven shaft on which the centre oneway is - as soon as power is applied (i.e. the shaft starts to spin faster than the front wheels) then the front wheels will be driven independent of what is happening at the rear. But as the rears are also driven from the very same shaft then they also rotate at the same speed as the fronts - assuming of corse the gear ratios are all correct.