im looking at the bocca bearing kit and it comes with two 8x16x5 bearings for the diffs. but on the traxxas parts guide it says that the bearing in the rear diff. is 8x16x4 and the one in the front is 8x16x5. is the 8x16x4 in the rear a mistake or is it really 8x16x4 and a 8x16x5 will also work. does anyone have this kit?