What kind of gear oil for 8 3/4? Why not synthetic gear oil?

I think the line of thinking comes from back when the "new" synthetic oils were coming out. Could clutches/cones be designed to perform properly with synthetics, yea probably, but with anything non-standard, the manufacturer would rather reccomend what they know works, vs doing the research and testing everytime a new oil type hits the market.

Just like how you have to turn off your electronics during take off and landing. Are you going to crash the plane with your Iphone? No probably not, but with technology advancing so fast, you never know, so the standard is to turn them off..