A vehicle’s differential (or diff), whether front (FWD), rear (RWD), or both (AWD), helps deliver power to the axle(s) and regulates how fast each wheel rotates. Like any other component of a drivetrain, differential problems may arise over time.
Because the issues can be anything from replacing a seal to a complete rebuild or replacement, differential repair costs can vary greatly. Read on to find some average prices for front and rear differential repair, rebuild, and replacement costs.
What is a Differential?
A differential is a mechanical device that allows a variance in wheel speed between wheels on a single axle. When you go around a turn, one wheel travels a shorter path than the other. If it weren’t for the differential, the tires on the driven wheels would want to scrub or skip as each tire tries to “meet in the middle” to match the rotation speed of the other.
Differentials are found in all cars. Depending on engine placement and how many wheels are driven, the differential can be found on the front axle, the rear axle, or both. Sometimes all wheel drive (AWD) vehicles have a center differential which allows the tires on the front and rear axles to spin independently of each other.
On a transverse mounted engine, front differentials are typically integrated into the transaxle. A transaxle is a compact unit consisting of the transmission, differential, and axles. If you have a transaxle and a rear differential, the rear differential likely uses a different type of gear oil.
Some vehicles (notably Subarus) will integrate the transmission, front, and center differentials all into a single unit.
Usually, when a vehicle has a front differential with a built-in transaxle, it will require a fully synthetic oil (SAE 75 to 85, for instance). Transmissions typically require a slightly thinner oil than rear differentials, which need a thicker oil that’s around SAE 90. This will of course will vary depending on each vehicle manufacturer’s specific implementation.
Average Differential Repair Cost
The repair costs of the front and rear differentials will fluctuate based upon the repairs that are needed. Sometimes you may only have to adjust the backlash or replace the oil seal of the differential. These are light repair jobs that will cost between $200 to $400, depending on the make and model of your vehicle.
But if you have more extensive damage to your differential that requires it to be dismantled or overhauled, then you are looking at about $400 to $800 in repair costs. However, these costs are only associated with vehicles that are front engine with rear wheel drive (FR) type.
If you drive a vehicle that is front engine with front wheel drive (FF) type, then the repair costs of the diff will likely be more expensive because the transaxle has to be pulled down and dismantled first.
This takes more time for the mechanics to do which means the hourly labor costs (typically around $85/hour) are going to add up fast. On average, replacing a front differential is about a 3 hour job plus the cost of parts of course. More advanced types of differentials will also affect price.
Differential Maintenance Tips
The trick to keeping your differential working smoothly is lubrication. You need to change differential fluid regularly so check your car manual to see what the recommended differential fluid change interval is.
The differential gear needs to be lubricated consistently or else the car will not drive or turn properly. Two of the most common causes of differential damage is due to lack of fluid or fluid that hasn’t been changed in a long time and is past its lifespan.
Therefore, you need to ensure that your differential fluid/oil is in good condition and is filled to capacity according to what the manufacturer recommends to keep the differential in good working order.
With all the friction that occurs in the differential gears, it is very easy for the gears to overheat. Good quality differential fluid will prevent the gears from burning and getting worn out.
You’ll know when you need to replace the differential fluid because you will start to hear a humming noise coming from the differential side. You may even experience vibrations, fluid leaks, and even some strange noises as the symptoms get worse.
How to Check Differential Fluid Condition
It’s simple and should only take about 10 minutes. Just open the filler plug, then put your finger on the hole filler and then you can see the fluid level and its condition.
And to make it even clearer, briefly open the drain plug so a bit of fluid comes out into a small tray. If fluid doesn’t come out, the level is too low and more fluid should be added.