So I just bought a 2006 Goldwing. I want to change all the fluids, filters, and plugs so I have a baseline of where everything stands. The manual says that the final drive gear oil should be SAE80 (straight 80 weight). I couldn't fins straight 80 weight in the auto parts store, but I have some Lucas 75W-90 gear oil in the garage. Will this work or should I get something else? The only other thing I can find at the store is the Lucas 80W-90 gear oil. Would that be better AND is it the same as what the manual recommends.