And,
one more. I believe this test was done on a single gear set (just two gears), not a whole gear box. So, the power losses should be lower than in a automotive transmission. However, this is the best data I've found thus far. It gives a range of temperatures tested, and at speeds we would see in our application.
By looking at this chart, it looks like at 2000 rpm, increasing oil temperatures should be able to very roughly half the losses to the transmission.
