^^ sorry Ian, by 4WD I meant Haldex. Although you could remove the prop on a proper 4WD car (not on a dyno day with a queue of cars behind)
I don't understand the mechanics of the box, but the dyno should remove the haldex losses like it does with a standard gear box to work out the flywheel figure. As we all know flywheel figures are just from calculations of wheel figures.
The fact that many people dyno haldex cars and I've never heard of a failure as a result of it, I'm not sure what the problem is? Open to a lesson in haldex mechanics and the dangers of dynoing in 2wd mode from any specialists. It's not really been discussed on this forum. . .