Although you may not have been aware of this, turning a car’s wheels will make them spin at uneven speeds. By default, they do not even travel the same distance. Basically, during a turn, the wheels on the inside rotate at lower speeds than the ones outside the turn. Although in the case of free axles this is possible without any problem if the axle is a motor, the wheels cannot rotate independently of each other without the existence of the so-called differential.
Therefore, the differential is the one that takes the torque and speed of the engine through the gearbox and then transmits them to the drive wheels. Moreover, due to its operating principle, it is able to distribute the torque differently.
How Much Does Differential Repair Cost?
Differential repair costs are influenced by some factors such as the make and model of your car, the mechanic you choose, the place where are you living, the location of the differential (front or/and rear), the parts that are used to repair the entire differential and the complexity of the repair. However, the average cost for differential repair would be anywhere between $550 and $2,200.
It would take around six hours to remove and rebuild a non-locking differential, while the repair time of a locking differential is around eight hours. Taking into consideration that a mechanic charges around $90 per hour, the labor costs would be somewhere around $720. It would be pretty hard to say what parts have to be replaced until the differential is torn down.
Expect to spend anywhere between $210 and $550 for a light repair of the front-engine rear-wheel drive, such as replacing the oil seal causing a leak. On the other hand, the cost of a difficult repair like rebuilding or overhauling the differential is anywhere between $720 and $1,110.
Though, the cost of repairing the front-engine front-wheel-drive may be a little higher because the mechanic will have to pull down and dismantle the transaxle in order to resolve this problem.
Depending on the mechanic you choose and the oil you need for your car, you will have to pay anywhere between $75 and $160 to change the differential fluid.
According to the Trail Transmission website, you should plan on spending anywhere between $720 and $1,300 to rebuild a differential and around $1,600 for a brand-new rear differential.
One member of the Stack Exchange forum said that it would cost you almost $2,350 to buy a new differential for a Ford F150, or around $1,250 if you chose to purchase used parts.
The differential is a mechanism based on sprockets similar to those in the gearbox that allows the wheels responsible for traction to rotate at different cornering speeds.
In all-wheel-drive cars, there can be three differentials: one for the front axle, one for the rear axle, and another central one (between the two axles), the latter being necessary due to the fact that the front wheels only rarely rotate with the same speed as the ones behind.
Types of differentials
It is the most common type of differential in the case of production cars, being also the simplest (and the cheapest for the manufacturer). It consists of gears, the main pinion, two secondary gears, and two more that are directly connected through the planetary gear. The main sprocket is the one that receives the torque from the engine and then transmits it to the planetary gear through the other pairs of smaller sprockets.
Differential locked (self-locking) or “closed”
If at the open differential the two pinions connected by the planetary gear were welded together, regardless of the rotation of the steering wheel or the available grip, the two wheels would be forced to move simultaneously, with the same speed of rotation. It is the simplest explanation of the locked differential.
Self-locking systems have different systems (mechanical, pneumatic, hydraulic, etc.) designed to ensure the locking of the internal sprockets, but this is the basic principle.
Limited Slip Differential
A simple definition of Limited Slip Differential is the following: the limited-slip differential is a compromise between the “open” differential and the locking differential, capable of behaving similarly to the blocking differential in situations of significant imbalance of grip and similar to the open differential, in the basic application of the differentials, the one that allows the rotation with different speeds of the wheels in the turn.
Torsen type differentials (Quaife, Peloquin, etc.)
Torsen is a term derived from the expression “torque-sensitive”, which describes the very operation of the system. It is the type of differential whose main feature – which also resides in its quality and performance – is that it reacts immediately to any torque imbalance between the two drive wheels, directing the torque to the wheel that can successfully transfer it to the rolling surface, i.e. towards the wheel with high grip.
Important things to consider
Depending on the type of differential that your car has, we are talking about easy or complicated maintenance. An open, ordinary differential requires only oil, good gaskets, and if it makes a sound, the replacement of some bearings. But a self-locking differential also needs the change of the clutch discs or the spring that makes it locks the other wheel.
Although their original role is to provide increased grip on any surface or to get you out of the snow and ice buildups in the winter, many use them to drift as well. Regardless of the situation, a differential is an interesting piece that we need to take good care of.
How can I save money?
You may be able to save up to 50% if you choose to rebuild the differential instead of purchasing a new one. This is also available for the aftermarket parts, which are 30% to 40% cheaper than the OEM parts. Make sure you talk with your mechanic about your options.