you could go to a arm on the servo instead of the servo saver style that comes on it and see if that will do anything any different. i am assuming that the gears/shaft for the forward/reverse mechanism were all in good condition, the servo movement with a solid arm should move the mechanism and hold it no questions asked. i am going to change to that linkage as soon as i get the time, but havent had a problem yet. you could have slightly tweaked the shifting fork when you broke the shaft, if you dont use the high/low much you could switch them and see if that helps since it stays locked with the knob.