Having trouble finding the problem on a revo 3.3 nitro model. I was running fine and then after a few roll overs it doesn't want to switch from forward to reverse without driving in the opposite direction first then it slams into gear. This happens in both directions. I've pulled the tranny and everything looks new inside, shifter linkage looks good also. Tuning seems to be good, shifts great from 1st to 2nd and idles well. It does try to take off as soon as you try and crank it though. Any help is appreciate