Okay so I have the t98 in my 51 f1 that I am building and it has the v8 and for the moment the body is off of it. So I drove the chassis around this summer and when I would put it into reverse and back up and give it throttle it would whine (normal) but when I would let off the throttle it would grind and make bad noises. It only does this when there is back pressure on it from slowing down. What is the issue???