Kuhn GMD 500

Took a quick look-see at an older GMD 500 today.  Probably going to have fewer animals on the land than last summer, so was kicking around the idea of putting some grass up as bales this year.  If I did I'd try to borrow most equipment, but just on general principle it seems like if I'm going to bang a cutterbar off of rocks I'd rather it be mine, so I'd like to own the mower at least.  Would probably want to use it for some end of season trimming too. 

 

Machine seems to be in pretty good shape for the age, no visible weld repairs anywhere, no oil leaks on the ground.  Cutterbar was very tight, but felt like there was some slop in gearbox--is that normal with some form of clutch for shock protection in there or a red flag?  Also the first disc looked about 15 degrees out of time, but no evidence of contact between discs. I seem to recall reading somewhere that those generation of mowers had unique first disc/blades--does that explain it? Or am I totally making that up?  Any particular weak points on those mowers?  Seller is asking $3500.

 

Thanks for any thoughts.

Kuhn GMD 500