It was actually a very common thing for me and a buddy of mine to stip out servo gears in our old T3's. We figured that dirt was getting in between the servo saver tube and the plastic servo arm pieces that slide on that tube making it all jam up. I tried to drill out the plastis servo arm before sliding it on the tube, and polishing the tube, but nothing worked. Dirt would just get in there and bind it all up. the only solution is to get a metal geared servo and be done with replacing servos.