Looks like it is welded to the frame there. Hard to say, but you should be able to get a better eyeball on it. Final drive oil I liked a full synthetic . Most "whine" is usually from the clutch basket. But with a lower gear ratio I could believe it makes a bit more noise. I think 70w140 may be the weight I ran, but check the service manual. There are a couple places one is available from download free.