1. Did you try the batteries. Are they fresh or freshly charged. I run energizer rechargables in my nitro rusty and have never had a problem, just recharge them every day I bash.
2. Is your radio dry? Did you run in some water? If the servo is making wierd noises, it might have dirt in it. You can take it apart, but has a lot of gears in it. Any standard size servo will work... you don't have to use traxxis servo. Use denatured alcohol to clean everything and then blow with air compressor.