WTW, gear lube leaking from my swingarm cap

[T in NC]

When I got home Sunday night I noticed some gunk on my right muffler, then this, Does the transmission vent through there that is definitely Shockproof Heavy?

[kevdog3019]

When I got home Sunday night I noticed some gunk on my right muffler, then this, Does the transmission vent through there that is definitely Shockproof Heavy?

Could it be gravitating there from somewhere nearby??  I'd check out the scene around that vicinity. Can't imagine there's any way for it to directly escape from the gearbox through that mount.

[mtiberio]

good trick, can't imagine how that is happening, since the hole behind the bearing is blind...

[Warwick in NZ]

Maybe water has got into the bearing grease??? looks very milky to me....Warwick   

[Vasco DG]

Steve, if the bike is post 2002/3 the swingarm stub-axles are hollow. Migration of oil either from the bevelbox or from the gearbox seal or o-ring can get into the UJ area and on these later bikes which have a different UJ 'Compartment' for want of a better word which doesn't have a 'Blind' hole the oil can then be thrown around and will leak out as you see.

What to do about it? Well. First check the oil levels in both gearbox and bevelbox. The front, pinion,  bearings of the bevelbox aren't sealed and it is not uncommon for oil to be flung forward, through the bearings and migrate up the shaft tube/swingarm. This is compounded if the bike is running heavily laden with the suspension compressed. When you stop the oil will tend to migrate back to the bevelbox but some is obviously escaping. If it isn't the bevelbox then it is going to be either the output shaft seal or the output shaft o-ring. Unless the level in the box is low it is unlikely on a box of this vintage with the extra crush shim for the o-ring to be the o-ring or seal unless....

A.) The breather is blocked.

B.) The 3205ATN9  bearing on the output shaft has shat it's ball cage and pushed a bit of cage through the seal.

My money is on it being simply oil migration up the swingarm into the UJ housing and it then weeping out through the stub axle but it's worth pulling the swingarm to check that there isn't a great chunk of bearing cage poking out through the seal.

If it looks good and there are no strange noises from the gearbox, no serious oil level drop in gearbox or bevelbox, and no other issues I'd just suggest cleaning the lock nut thoroughly and sealing the little rubber plug with threebond so it can't leak. BUT you must make sure that all the above checks get a tick before just sealing it up.

Pete

[T in NC]

Thanks, Pete. Some of that was what I  expected. I haven't had time to check the fluid levels  yet but I will before I  go out again. I suspect your right about the bevel box. I had just never seen oil come out there on my 850T. But if the swings axel is hollow it kind of makes sense. Thanks

[Wayne Orwig]

I had the swingarm off of a 2003 a couple of times this year for other reasons. It was running the "pink slime" too.
What I found was that the transmission rear seal was leaking into the rubber boot area. It was not leaking past the carrier bearing and stayed trapped near the transmission. As in, the rear drive lube was not migrating forward as far as I could tell. I replaced the rear transmission seals and o-rings, and did the other repairs. Refilled with normal lube. After assembly, it still leaked "pink slime" there. So it was the left over oil in the swingarm, which I had not cleaned it.

The short version: On the 2003 and up wide swingarm, any oil in the rubber boot area easily leaks there. If it is leaking badly you may have a leak from the back of the transmission. Keep and eye on the oil levels.

[mtiberio]

... these later bikes which have a different UJ 'Compartment' for want of a better word which doesn't have a 'Blind' hole the oil can then be thrown around and will leak out as you see....

live and learn... someday I'll be pulling the swingarm off my calvin and I'll see this...

[T in NC]

Bevel box was spot on at 250 millimeters, but the transmission was down about 650 to 675. I refilled with 750 ml and added 50 more to get it to dribble out of the plug that is suppose to be the fluid level plug. So I may have a bad seal, seems a bit early at only 12000 miles. Anyway I forget do you have to pull the motor when you pull the trans? And I guess I should replace the bearing while its out, right?

[twhitaker]

If there is a vent line from the transmission you might check to see if it is pinched.

[Wayne Orwig]

Anyway I forget do you have to pull the motor when you pull the trans? And I guess I should replace the bearing while its out, right?

You can replace the seal, and maybe even the oring under the speedo gear, with the transmission in place.
But of course bearings and such require that you crab the motor in the frame.

BTW, once the swingarm gets filled with the 'pink slime', it will tend to keep coming out for a long while, even after sealing it up.