Radio is an XP3-SS, servo was the stock rtr model and a Savox 1258TG. After running on the track for a few minutes the the servo would get re-centered. I thought it was the stock servo at first, but it continued to happen after installing the Savox. The Savox now has a center that isn't where it was initially. Is there a way I can reset the center without bouncing the truck around and waiting for it to happen again? I have access to an MT-4 as well. Thanks in advance.

After more testing I found that the servo arm is stripped just enough that with a hard hit it will move a tooth or two. I didn't notice in the beginning because it takes more force than I was exerting to get the arm to skip.