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A rookie question about drive shaft / final drive lubrication (on Mille GT or similar)

blues_mack

Just got it firing!
Joined
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Zagreb, City of Zagreb,Croatia
Hi everybody!

I recently bought 1989 Mille GT, I got no previous experience in old (or any) Guzzis. Yesterday I took the wheels off for tire change, and I've noticed that drive shaft rubber boot, rear cover of gearbox and right leg of central stand have some oil on them.

Previously, I've owned a monolever BMW R80 RT and did a lot of wrenching on it.

Transmission-wise, BMW had 3 lubrication chambers separated by oil seals: gearbox, shaft and final drive.

On my Guzzi so far I didn't find any clear information about oil seals except the seal on output of the final drive. I need to understand this better.

I suppose gearbox output have an oil seal? Can it be replaced from the drive shaft side, without opening the gearbox?

Other than that - is shaft lubricated on my bike? I can find only information about gearbox and final drive oil change, but not about the swingarm shaft chamber.

Is it possible that the shaft's U-joint isn't lubricated??

(I've also noticed on some exploded views that the swingarm to frame connection have oil seals, and that confuses me even more)
 
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Hard to say where the oil is from. Could be gearbox output seal, engine vent, and so on. Clean carefully then ride and inspect for source. The rear drive has two seals, an inner and outer seal. If the rear drive seals leaked it would show on the rear wheel. The drive shaft is not lubed by oil and the cardan joint (double U-joint so it is a velocity joint) is sealed. Oil will come up into the swing arm from the rear drive, but it will drain back into the rear drive. Considering the age of a Mille, the boot may be cracked if it was never replaced.
 
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Yes, gearbox output has a seal, it can be replaced without opening the gearbox.

Cleaning and greasing all of the splines on the u-joint, driveshaft, coupler and rear drive input are all that's required.

Yes, there are seals at the swingarm pivots, those keep the grease in the tapered roller pivot bearing and dirt/water/etc. out.
 
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