Running in reverse if different to running upside down. Our diffs do not run in reverse, they use conventional Dana 60 and Dana 80 gear sets.
There is a case study explaining the disadvantages of running diffs on the COAST side of the gear set (Different to running upside down, where they still run on the drive side - BIT confusing for some...)
9" and 10" gears have a UNIQUE gear pattern than makes them VERY strong when driven on the drive side, but when they are run in reverse, the gears are much weaker and try to tear themselves apart.
I have seen a lot of mid mounted cars running massive (EXPENSIVE $$$) 10" gear sets in the rear, running them in the wrong direction (COAST SIDE) - making their drivetrain much weaker. The correct thing to do is to run a reverse rotation (Vee Drive) to correct the rotation at the pinion and run the diff on the DRIVE side, where it is the strongest. Hope this helps explain it???