Gear lube leak at the engine boot

[ecstag]

(previously posted on another page. sorry, should have posted here first)

Can I get some opinions on the cause of my gear lube leak at the engine boot? Here are some facts:

1. Bike is a 2003 Vulcan 1600 with 18,000 miles
2. Does not leak on short rides with 1 up. Have had it up to speeds of 80 mph.
3. Will leak on 1 up rides of long duration....like 100 miles of high speeds (65 to 80 mph).
4. Will leak all the time with 2 up, even on short runs.
5. Leak is only a few drops when the bike is at rest.
6. Leak is gear lube, not engine oil.

Thanks....

[Classic]

Bad seal in the differential allowing gear lube to run up the shaft housing and out the boot. Not a huge leak from your description but it should be repaired.

[RichLockyer]

+1
The problem with not repairing it and just topping off the final drive is that the gear oil is washing the grease out of the slip joints on the drive shaft.

It's leaking more 2-up because of the increased angle of the swingarm causing it to ride "nose down", which allows the oil to flow more freely from the final drive to the front and into the universal housing.

It's not a HUGE deal to replace the seal, but there is a peened nut on the final drive's input shaft, and I believe a couple of special tools are needed.

[rfb92345]

Rich, you can replace the seal without removing the pinion nut (which does require a special tool). Caefully work the old seal out, then install the new one with a pipe nipple and cap of proper size.

[RichLockyer]

I thought the seal was under the pinion nut.
When I pulled my swingarm, I didn't see a seal in the front of the housing... just the peened nut and a washer under it. I assumed the seal was under the washer.

[RichLockyer]

Ya... looking at the diagram now.
I suppose it might be possible to get that seal out of there, but it doesn't look like the new one will go in without damage.
Part #16 is the culprit.

[rfb92345]

All I know, Rich, is that on my '96 1500, the new seal dropped right in. All I had to do is seat it. Looking at the diagram, I'm not seeing what you are seeing. Maybe your 1600 is different, but that seem a little unlikely. The seal was very visible to me, but it sits down deep. I wasn't sure that I could get it out. I did get it out and the new seal went in very easy. Mine has not leaked since. A special tool is required to remove the pinion nut. I'm glad I did not need it. I can't imagine where I would ever find one and hate to think of how much it would cost.

[ecstag]

Hey guys,
Very good information. I'll be working on this thing soon and will let you know how it goes. But, before doing so, pls give me a better idea as to how the seal was removed. What tool and technique did you use to remove it?? Evidently, lots of patience goes with it.
Thanks for the info...
--Eddie

[rfb92345]

Yes........If I remember right, I tapped one side down as far as it would go. The opposite side lifted up and I was able to lift it out with heavy hook type dental tool. Just have to be careful not to gouge up anything. Just don't be in a hurry. I think it took all of abot ten minutes to change the seal after the gear box was in my lap. Don't forget to lube the inner lip of the seal before you put it all back together. Good luck.