It could also be the gears inside. If it has some time on it, you may want to rotate the gears. This way it has fresh gear on fresh gear and takes the slop/twitch out of it.
Any servo will do this after some time. Any experienced RC person will know this. And it is a piece of electronics, sometimes the servo's just puke out.
I have an Ace servo, a 1015, that has 2 1/2 years of 1/8 buggy on it. It's now in my crawler and still holding up. It's been in my crawler for almost a year now. Some people will like certain things, some people won't. I will never trust a hitec servo in my rigs again for steering or throttle. Some people will never like the Ace/AE stuff? Anything wrong with either of them? No. Just different opinions.