Speed passion problems

[Team 36]

Hi I have speed passion reventon 'R' esc with speed passion 8.5t motor I have used it in 2wd buggy with no problems but now I have put it in 4WD buggy and yesterday after 4 mins it would lose all power just lip round but not cut out when got back to pit table switch it off than back on it would fine to race again same thing would happen again it has a over heat protection on the program card so plug it in was at 95% not sure % it should be also the spur gear is 85T with 22T pinion so I can't see it been the spur & pinion making it hot any advice would be good