Introduction: Differential Gear Box Oil Change

Do you own or operate a pickup truck? Have you ever wondered how you can make it last the extra mile? Today I will show you exactly how to that. Making a pickup truck last the extra mile is done by an assortment of steps - some of which include regular oil changes, replacing your oil, fuel, and air filters and changing or checking the oil of a transmission or differential box.

Step 1: What You Will Need

What I will be teaching you how to do today is how to check the oil level of a differential box and change it when necessary. Differential boxes are used on every vehicle but pickup trucks grant much easier access to them. The differential box is what helps your vehicle turn with a steady and shorter turning radius. It also helps to reduce the wear and tear on a vehicles engine and transmission components. For this project we will need: oil of the correct viscosity (see owner’s manual), an impact driver or ratcheting wrench, liquid gasket of your choice, an oil catch bucket, a torque wrench set with the correct torque rating, latex gloves (optional), owner’s manual, and a small scraper.

Step 2: Removing the Bolts and Cover

It is recommended that latex gloves are used for easier cleanup. Along with the latex gloves, make sure to grab the rest of the tools needed for this job. Start out by finding the correct socket or wrench size to fit the bolts on your differential box. Then, begin by removing the lower bolts and work up. The bolts might take an initial good amount of force to break loose but it is very unlikely the bolt will shear off. The very top bolt or bolts should be the last to be removed. Once these bolts start loosening, oil will likely start to poor out. It’s recommended to place the oil catch pan underneath the differential box prior to taking the bolts out but is not required. Upon loosening the last bolt or bolts, the oil should be given time to drain out slowly. Failure to do so may result in an oil spill.

Step 3: Removing the Cover and Cleaning

Once the oil has slowed to just a trickle, the bolt should be removed completely. The old gasket should come off with little force and a small scraper is recommended to completely remove it. A shop rag or paper towel can then be used to wipe off any remaining residue from the gasket and soak up or pull out any remaining dirty oil from the box. Cleaning both contact sides of the box and cover is very important. Without proper cleaning, the differential box will leak and cause failure to the gears inside.

Step 4: Applying the Gasket

When both contact surfaces have been cleaned and prepared thoroughly, the cover and new gasket are ready to be reinstalled. Take the liquid gasket and start applying it to the differential box. Where the gasket application is first applied does not matter. There should be a ¼ to ½ inch thick strip placed all the way around the box. The end of the strip should be directly on top of the starting point. Make sure the gasket line is continuous and surrounds the bolt holes.

Step 5: Installing the Cover

Now that the new gasket is applied, the cover is ready to be installed. The easiest way I have found to do this is to take two bolts and place them in the holes on opposite sides of the cover. Hold onto these bolts and lift the cover up and in line with the differential box. It is very important that the cover is put directly onto the box and not shifted more than half an inch. The bolts should line up with their corresponding holes and can be twisted in by hand as far as they can go. Now, proceed to install the remaining bolts until all holes are filled. After all bolts are placed in their appropriate holes, they should be tightened just slightly, moving from top to bottom, in a crisscross pattern. Next, set the torque wrench to the appropriate torque rating (see owner’s manual) and begin to tighten the bolts down, once again, in a crisscross pattern, until the desired torque is reached.

Step 6: Fill With Clean Oil

After all bolts are tightened and checked twice, the oil fill plug can be removed and fresh oil poured into the differential box. (Oil with the correct viscosity is always recommended and the oil viscosity in the differential box, on any vehicle, is likely going to be very thick). When oil begins to slowly come out of the oil plug opening, the differential box is now filled to the correct level of oil. Quickly put the plug into the hole to keep all oil in the box.

Step 7: Clean Up

The last step to any project is always the same. Clean up all tools by wiping them off and putting them back to their appropriate location. Any fluids, such as oil, should be disposed of properly. After all tools are put into their appropriate locations and all fluids have been disposed of properly; the job is done. This simple oil change can allow a truck or car’s drive train to last the extra mile.