Concrete or black top are the best surfaces to use. . Never jack up a vehicle on grass, dirt or gravel as the jack may topple over.

If you are unsure where to locate your car’s designated jack points, refer to the owner’s manual for guidance. The height required to comfortably access the differential will vary from vehicle to vehicle.

Lower the car slowly onto the jack stand, to ensure it is placed properly and will support the weight of the vehicle.

While you can sometimes raise the entire rear end of the vehicle from jacking it up from a mid-point, there is a higher likelihood of the vehicle tipping off of the jack and getting damaged when doing so. Be sure the jack stands are holding the vehicle and that it is stable.

Be sure all of the jack stands are set to the same height so the vehicle is as close to level as possible. If you have access to a lift, it is a much faster and easier way to raise the vehicle at an even height.

The rear differential is easy to identify, as it connects the transmission to the wheels. Because of its vaguely pumpkin-like shape, rear differentials are often referred to as a car’s “rear pumpkin. ”

If the rear differential has been damaged, it will require service from a professional. The fill/service plug is usually not a traditional looking bolt, but rather has an opening for a 3/8 inch drive ratchet.

The brake cleaner will evaporate quickly, leaving a dry surface. Use the brush to remove large deposits of stuck on dirt.

In some applications, the plug may be a bolt. In these cases, find the appropriate sized socket to remove the bolt. Be extremely careful not to strip the bolt. Be sure to use the correct size socket.

If your finger touches gear oil, there is enough fluid inside. If the fluid level doesn’t reach the service port, it is low.

You can also ask the clerk at your local auto parts store to assist you in finding the right gear oil. Purchase gear oil that comes in a squeezable plastic bottle with a spout unless you have an oil pump to use.

Make sure to wipe up any fluid that leaks out of the open service port. If the differential takes an entire bottle of gear oil, you may want to have the differential looked at by a mechanic to address any possible leaks.

Do not overtighten the plug, it needs only to be tight enough to be secure. Remove the jack stands and lower the vehicle back to the ground.