There could be something wrong. With winter approaching you could always send it in to Futaba to have them check it out. My TX has logged some 80 hrs on it since I bought it a year ago and I plan on sending mine it this winter for a checkup. It wouldn't be too uncommon for issues to arise from a jolt here and there. On an unrelated subject, a guy at my flying field sent his JR radio in and the techs found there was actually a piece missing from the circuit board! Not sure what it did but thankfully he didn't lose any planes.

NiMH batteries, while better than NiCd, still have some memory. Cycling them can fix that. Depending on your charging/discharging habits this could also be the problem. If you don't have a battery cycler and plan on staying in this hobby I would definitely get one! If you know someone who has one you might borrow it and try that.