Ok, I just read a pretty interesting article that breaks down torque split, diff locking, and how they work pretty nicely. For those who care, I'll break it down, since work sucks, and I'd rather post about car tech.
First thing to know is what Torque is. Torque is twisting force, like if your turning a wrench, the force being applied to the nut is the torque. Next, you need to understand another important little tidbit. Newton said "For every action there is an equal and opposite reaction". In other words, if you push on something, it's gonna push back. This comes into play when dealing with traction, to put it simply, a car will only exert enough torque to rotate a wheel up to the point where it loses traction. As soon as the car breaks traction, the car stops producing additional torque at the wheel. To get a better idea of this, imagine you're on an excersize bike: If you drop the resistance down to nothing, and start pedaling, it only takes a little work before the thing is pretty much going on it's own, if you pedal more, it just goes faster to the point where it's going so fast that you can't move your legs any faster, with you having done very little actual work. That would be like having a wheel with no traction. Now, if you cranked the resistance up higher, and started pedaling, you would notice your legs would start to get sore, and you would have to work alot harder to get the wheel moving to where it's moving on it's own. That's similar to a wheel with traction accelerating a car. You can see how something would stop producing torque if it's not needed.
This comes into play when trying to figure out where the power is going in a given situation. Since the car will only put down enough torque up to loss of traction, if it takes 10ft-lbs of torque to spin the front wheels, that's all they'll see. So taking into acount the torque split, 10 to the front would be something like 18-20 at the rear, which may not be enough to get the car going.
Remember, with open diffs, power will go the path of least resistance, so while it may take 100lb-ft to move the rear wheels, the car is gonna take the easier route, and put down the 10 to spin the fronts first.
Now, if the diff was locked, in the same scenario, again, 35% of the engine twisting force will go to the front, 65% to the rear, HOWEVER, since only 10ft-lbs are needed to spin the front wheels, that's all they'll see, the rest will go to the rear. So, if you're putting down exactly 100ft-lbs, the torque split would be 10/90. Weight distribution, load, engine torque, and all that also comes into play. So under some situations the torque split may be 50/50, it may be 90/10, or 10/90, all under the same locked diff. However, the car will always try to send power in a 35/65 split.
Ain't car tech/physics grand.
I understand this contradicts what I posted origionally, so keep in mind this is real world, what I posted first is in a perfect world. With the diff locked, and the car in the air, power will be split 35/65.
