In my teenage years, need I say more, I managed to shear the pinion gear shaft off the rear differential on the car I was driving. Unattached to the differential the driveshaft was rotating at high rev's hitting the ground and then the underside of the car. I thought the pistons where coming out of the engine as the car shaked violently as the driveshaft kept loudly hammering the underside of the car.

So at 16 my best friend and I figured out how to replace a differential.