If you own a rear wheel drive car, truck or SUV that is at least ten years old and Made in America, Auburn Gear probably has a differential, and other related products, to help you when you need to repair or replace your differential.

Many American-Built Vehicles Have Auburn Gear Differentials

For many years, especially between the early 1950s and 2000s, American auto manufacturers such as Ford, General Motors and Chrysler, installed Auburn Gear differentials. For instance, if your GM vehicle has a Positraction differential, it is probably an Auburn Gear product. For these and other vehicles, when you have the need for differential service or replacement you can probably find the ideal products at one of many Auburn Gear dealers across the country.

How do you know if your differential needs service, repair or replacement?

Whatever kind of differential set-up you have, you want it to be working properly. Here are some common symptoms of a failing differential:

1. Service Past Due

Like all vehicle components, your differential needs periodic service. The primary maintenance step is to replace the differential oil (otherwise known as gear oil) per the manufacturer’s recommendation. To understand your differential maintenance requirements and frequency, consult your owner’s manual (visit the “Support” section of this website).

• Leaking Differential Oil

To most people, differential/gear oil looks similar to engine oil when leaking out the bottom of the vehicle. So try to determine where the leaks are coming from. If the leak is directly under one of your axles (especially the one corresponding with your front- or rear-wheel-drive system), then there’s a good chance it’s a differential leak. You should fix this as soon as possible to prevent further damage to the wheels, axles, drivetrain or transmission.

Leaks will most likely be at the axle seals, the pinion seal (where the driveshaft attaches), or the rear differential cover. Light brown or grayish fluid on the ground under the back of your vehicle is an indication that you have a differential fluid leak.

3. Strange Noises

Failing differentials often produce loud whirring noises or sometimes rattling. Any time you hear a strange noise coming from your vehicle, you should get it checked out by an auto repair expert. It can be any number of problems, including the differential.

Unfortunately, if you hear a whirring noise from the back of your car, it’s probably too late and a rear differential repair is required.

4. Vibrations

Another common indicator of a differential problem is experiencing unusual vibrations while driving. However, like other symptoms, it can be a sign of many different automotive issues that are worth getting looked at by a professional mechanic.

5. Unusual Smells

When the differential oil goes bad, it will start to thicken and burn. This can cause the internal gears and other components to seize up or break. If you notice a strong burning oil smell, take it to your mechanic immediately. You may just be due for a regular oil change or it could be the differential oil deteriorating.

What Types of Differential Service May Be Needed?

Replace Your Differential Oil

The gears in your rear differential are bathed in gear oil to lubricate the gears and bearings and to cool them and prevent overheating. The fluid breaks down over time, and metal filings collect in the fluid. Occasionally your differential fluid must be replaced to prevent damage to the gears inside, known as the ring gear and the pinion gear.

Changing the differential oil is one of the most-overlooked maintenance tasks on non-FWD light trucks, SUVs, and passenger cars. Because the differential is at the rear and under the car, it doesn’t get the attention that the engine up front gets. But if lubrication in the differential fails, you won’t be getting very far for very long.

The good news is that you only need to change this oil every 20,000 to 40,000 miles.

Changing this oil is just as important as changing your engine’s oil, and for the same reason. Checking and changing the differential oil in a light truck is fairly easy, and it’s only a bit more difficult in a car. In either case, this procedure can save you a big headache down the road.

A rear differential service requires removing the differential cover, cleaning old fluid from inside the differential case, resealing the cover, and adding new fluid.

Depending on your differential’s design, this can be a very messy or a very tidy job. Drive your vehicle for a few minutes to warm the oil, and make sure you’re wearing clothes that you don’t mind getting very dirty. Some differentials have a drain plug; others require removal of the housing cover. In either case, you’ll need a wide catch pan; and a plastic drop-cloth beneath that is a good idea.

Next, be aware that old differential oil has a truly foul smell. So brace yourself and remove the fill-hole plug at the top of the diff casing. Unscrew the drain plug. If you there isn’t a drain plug, unscrew the housing bolts.

Pry the cover open gently or the oil will gush out. Do not damage the surface of the differential housing. Let the oil drain completely, then remove the cover.

Using a clean shop towel or rag wipe out the housing once oil has finished dripping into the catch pan, this will clean out small metal shavings that are considered normal ware, note any large chucks of debris as that could indicate a damaged differential.

When replacing the cover be sure to follow manufacturer recommended torque specifications and use a gasket sealing compound when/where required. Some manufacturers/models use a gasket seal that does not require this sealant, check with manufacturer specifications.

Once the rear cover has been replaced fill differential with Alburn Gear Oil until the oil runs from the fill hole and replace plug.

Differential Oil Leaks

If you experience a diff oil leak, you may need one of these fixes:

• Rear differential gasket replacement. The rear differential cover is typically silicone or rubber and can deteriorate and leak. This is the easiest repair requiring about an hour of work – just remove the rear differential cover, clean the sealing surface, and reseal the cover.
• Rear differential pinion seal. At the front of the differential is a yoke that attaches to the driveshaft. Over time the seal around the yoke can develop a leak. This is a little more time consuming repair. The yoke must be removed, the seal pried out, and a new seal driven into place without damaging it.
• Differential side seals. These prevent the diff fluid from leaking onto your rear brakes. The axle shafts must be removed. The old, leaking seals are pried out and new ones are carefully installed before the whole assembly is put together.

Other Rear Differential Repairs include:

• Rear differential bearing replacement. Differential noise can be caused by pitting and deterioration of the side bearings and the pinion bearing. These bearings are part of a rear differential overhaul, which can take three to five hours to complete.
• Replacing the rear differential gears. When teeth on the gears have chipped or worn badly, they must be replaced to eliminate noise and potential for failure. These are the most expensive components to repair.
• Complete rear differential replacement. If the gears have ‘grenaded’, the case might not be unusable. A complete rear differential replacement is required, involving housing, gears, bearings, seals, and all else.