i took from the battery size that he was just bashing around and not racing while having the problem. yeshe could change the fluid inhis center diff but i thought it would be easier to just swap in the slipper unit and see if that solved his issue. (assuming he already has one).if he is running at a track or does not have the slipper unitthen he can try tuning the center diff. i did try changing the fluid in mine though and it still had almost thesame effect on 3s. the diff is better for the track for sure but the slipper unit is more fun around the house anyway...wheeeelieeeees!!!lol