Its broke

I had a major break down over the weekend when on my way to North Scotland from Nottingham the rear UJ joint broke at about 70mph
two up fully loaded. Managed to stop without falling off but it was close. As any one else had one break without any warning.
The bike has done 73000 miles.

Someone else had a catastrophic failure, it was on this forum about 18 months ago, I will have a look for it.

Try this for starters.
http://www.ukgser.com/forums/showthread.php/406989-Final-Drive-fekked?highlight=FD+failure

Still quite a rare thing, however even on the old Air heads the clutch splines and drive shaft splines needed a coating of 'Optimol' paste to stop fretting , corrosion, at regular intervals. On the Paralevers even more so. The older shafts and clutch splines would fret and finally fail , leaving no drive.

I guess they still are not totally maintenance free and at higher milages probably worth examining and re lubing. Especially as water can get through gaiters.

If I was keeping my GS that long then thats what I would do every so often.