A standard third turns the opposite direction in the front (drive side of the gears) than it will when turned around in the front (coast side of the gears). This is why front ring gears break more than rear, they normally run on the weaker side of the gears. A reverse cut/rotation high pinion should, I believe, make the front differential run on the drive/strong side of the gears. The added benefit is the high pinion, but you don't run them in the rear because it would be max load on the weak side of the gears.
The only issue that I could think of from running switching a front to a rear is if the perfect setup for the coast side of the grears doesn't translate to a perfect setup for the drive side of the gears. Likely the noise previously referenced.
Chris - Is the setup procedure from Toyota the same for a front and rear differential or do you shim them differently based on the pattern on the drive or coast side of the teeth?
