From the video it looks like your diffs are either not tuned right or are just shot altogether. I've never been a great fan of ball diffs and much prefer tuning gear diffs with diff oils rather than tension with springs and thrust bearings. Read the manual for the recommended tension on the ball diffs. IIRC it is a certain number of turns out from fully tightened. Eventually a good brushless system will make short work of the stock setup. If you have the funds I highly recommend upgrading to the
MIP setup with
carbide balls in place of the stock steel balls on the
rebuild kit. You'll need two of everything for front and rear diff rebuild.