Gear whine

[dougster]

I know we have discussed this topic before. I am hearing a whine in 4th and 5th gears. I really started noticing it while I was on a weeklong bike trip last week.

1. It is intermittent. I don't hear it all the time, but it is more pronounced at some times than others.
2. It is not road noise or tire noise.
3. It is loudest (when it is making the noise) when I am maintaining higher speeds in 5th gear (around 75mph).
4. If I pull in the clutch, it disappears. It does not make the noise by revving the engine with the clutch pulled in.
5. It is less pronounced, and even absent, when I am accelerating or decelerating. But I can hear it some when decelerating.
6. I don't hear it in the lower three gears. (Even when up on the lift, listening with a dowel to the area).
7. I put it up on the lift, and ran through the gears, with light drag on the rear brake, and used a dowel to localize the sound. First time I did it, I could hear it in the gear box/u-joint area. Second time, it was gone.
8. The rear final drive is not making the sound. However, I am going to drain both the final drive, and the engine oil, and check both for shavings.

It seems to me that my problem is in the area of the front bevel gear. Can any of you see anything I am missing here? It seems it must be the bearing, u-joint, or bevel gear making the noise.

I plan to pull the rear end (wheel, swingarm, driveshaft) off and check the components. (Sure wish Mac or MAS or BD, etc lived close to me!)

I started to wonder if if might be possible that maybe the oil pipe on the top of the gear box might be partly clogged, and is sometimes not getting the oil to the bevel gears in the back of the box as well as it ought to, so they whine during those times, but not others?

Thanks in advance guys, for the help.

Doug