Always be sure your rear end is checked!

How's that for a catchy article title? I was debating on using that or "Be sure to lube your rear end" and decided to stick with the former rather than the latter. In this case, we'll stick to discussing your vehicle rear end. What you do with yours is your business.

The rear end of rear wheel drive vehicles and four wheel drive vehicles has an assembly called a differential. The differential is designed to allow the power from the engine to be transferred through the rear wheels. The driveshaft goes straight back into the differential and the rear wheel axles come in from the sides. The housing is filled with a special gear oil.

This "T" formation at the rear end that makes up the driveshaft and the axles, works by using a ring and pinion gear set up, typically. There have been advances that has changed this setup in a lot of ways, but for our purposes, we'll keep it simple. The point of intersection of these parts is in the differential. Due to the amount of friction that comes from the interaction between gears, bearings and clutches, a lot of heat can build up. Add to this by pulling trailers, off-roading, mountain driving or any other condition that can cause extra strain, and it can be downright brutal on the system. As the gear oil begins to break down, friction increases and temperature increases. Increase the temperature and friction on anything metal results in seizing. Seizing while in motion can cause a sudden breaking with force. I have seen holes in differential housings caused by metal shrapnel from the explosion of the gears. Not good.

The easiest, and most overlooked, thing to do is to be sure to change the rear end fluid at regular intervals. It's usually a relatively inexpensive service that can save you a couple thousand dollars.

Happy driving!