[Yosemite Sam]

I would definitely (at the very least) open the gear box and see what's going on in there.

They have a tendency to get water in them, if it does have moisture, I would take it apart clean it up, check the shafts and replace the bearings. If there is any wear on the shafts, contact Jeff in Pa, he can make new shafts for you at a reasonable price. Someone on ebay is selling gear box bearing kits also at a reasonable price, if you don't actually see what you're looking for, contact the guy, he has all the bearings, seals and gaskets that you would need. Bearings and shafts are easy to find and fairly inexpensive, you don't want to break the gears, they are pricey and more difficult to come by.

I personally have never had a chain case open, so I don't know what kind of problems may exist in there... But I'm sure someone who has will be along shortly.

Good luck.

Tilling with a Cub Cadet really is great fun!