From the very brief description it sounds more like the symptoms of a slipping clutch rather than a transmission problem. If that is the case then Whisper Jet's advice to check the oil type is spot on, for the wrong oil can cause the clutch to slip.
2006 Titanium GL 1800, ABS
2008 Tailwind trailer
Vast Right-Wing Conspiracy Member #1
RAT PACK 2013
I ride too fast, too far, and too often to ride anything but a Goldwing rolling on a car tire pulling a Tailwind trailer because friends don't let friends vote Democrat.