Every vehicle is fitted with either front or a rear differential, or both.
Some vehicles such as 4-wheel drive SUVs are equipped with both front and rear differentials which allows the vehicle to turn in different directions while the 4-wheel drive is engaged.
The vehicle’s differential delivers power to the axle and adjusts how fast each wheel will rotate. Once you approach a turn, the wheels start revolving at a different speed and this is only possible due to the differential.
Without proper working differentials, the car axles will fail and consequently affect the whole ride.
Differential Replacement and Repair Cost
The exact price of repair and replacement of differentials differs from car to car. Generally, the differential repair/replacement can be categorized into three types:
- Differential oil replacement
- Individual parts and component replacement
- Complete rear differential replacement
Differential Fluid Replacement Cost
The differential oil replacement is fairly cheap and can cost somewhere between $80 and $150. The price can be higher depending on the lubricant, labor cost, and taxes. For an SUV, the price might be higher than this. The whole process takes about 30 minutes in most cases and can be done at home with the right equipment.
Differential Repair Cost
When talking about the differential part or component replacement, it’s usually the gasket or the differential output seal which needs fixing or replacing. The gasket replacement can cost between $130 and $200 while the differential output seal costs between $70 and $340. The price can be lower or higher depending on the car model, car type, and labor cost.
If there are gears damaged inside the differential, it’s often cheaper to replace the whole differential with a used one, rather than replacing the individual parts inside it.
Differential Replacement Cost
The complete overhaul or the replacement of a differential can be costly if there are internal damages to the gears. It can cost somewhere between $800 and $6000 depending on what car you drive. The price varies a lot depending on whether you are looking at a brand new differential or a used one. Sometimes you can find used differentials in good condition for a good price, which will reduce the replacement cost a lot.
Signs of a Bad Front/Rear Differential
Like any other vehicle component, the front or rear differential are prone to damage. The cost of replacement or repair depends on the type of damage. Some issues can be fixed by servicing the vehicle, while complete differential replacement can cost you a lot. Here are some of the symptoms you might notice if your vehicle’s differential is damaged.
1. Difficulty in Handling
If you have a bad or damaged differential, you will have a hard time turning your vehicle around the corner, because it will be unable to adjust its speed accordingly. If the differential is extremely damaged, this can even lead to an accident.
2. High-Pitched Sound
Hearing a loud high-pitched noise is one of the most common symptoms of a failing differential. This happens if the differential is not properly lubricated and may be leaking fluid. Weird noises indicate loss of fluid, so properly lubricating the differential will fix the problem.
3. Damaged Tires
If both the wheels and tires travel at the same speed when turning the vehicle, the inner tires will get worn out quickly because of faster rotation. This will also damage the tire treads and can worsen the drive performance.
4. Increasing Vibrations
If the joints on your differential get damaged, the drive shaft will begin to vibrate. You will notice that the vibration will worsen if you accelerate. Moreover, if there is a leak in the differential fluid, the performance will drop even further. In such a case, you need to get your differential checked immediately.
5. Noise from the Differential Gear
If you have a worn differential, the gears will start to grind and will generate a loud humming noise. This noise may increase if you step on the pedal and accelerate. In such a case, it is recommended that you inspect the differential gears and check their condition.
Types of Differential
There are 5 different types of differentials, of which three are found most commonly in modern vehicles.
The open differential is the most commonly found in modern vehicles and is cheaper than most others. It performs the basic function – that is, allowing the car wheels to rotate at varying speeds. An open differential works best if the road is smooth, while rough or slippery surfaces can be problematic for this basic type.
A locking differential has an advanced mechanism of locking the wheels of the same axle together. This powers both of the wheels and the vehicle can, therefore, run more efficiently on a rough or slippery surface than with an open differential.
A limited-slip differential works alongside an advanced gear system or a high-performance differential fluid. It is mostly found in high-end racing cars.
The other two differentials are the electronically-controlled limited-slip differential and the torque-vectoring differential which can be found in expensive luxury cars.
Checking for Differential Leak
The differential fluid looks similar to the motor oil and has a distinct smell as well. If you have a rear-wheel drive and you notice some spillage at the rear, it probably means that the differential is leaking. However, sometimes the differential fluid leaks through the axle and gets deposited on the brake assembly. If this happens, you will notice that the vehicle’s braking distance will increase or maybe a noise will be heard when applying rear brakes.
Replacing the whole differential is a costly procedure especially if you have a new model. Thus, it is advisable to have your vehicle inspected by a professional mechanic as soon as you notice any of the symptoms mentioned above.
Hi, I’m Magnus, the owner and the writer of Mechanic Base. I have been working with cars for 10 years, specialized in diagnostics and troubleshooting. I created this blog because I was tired of finding false information on the web while looking for repair information. I hope you enjoy my content!