Every component of a vehicle has a specific job to keep it moving. However, it’s normal not to know how Semi-Truck Differential work. You may have come across terms like “limited-slip differential” or “open differential.” when shopping for a new semi-trailer combination. But what does a differential mean on a tractor-trailer, and how does it work?

How the Semi-truck differential work?

A semi-truck differential allows a truck’s outside and inside wheels to move at different speeds along curved roads. Distribute the same torque to each wheel. Without them, the truck loses traction when turning, leading to axle and tire wear problems.

Differentials provide independent rotation of the wheels. These components provide proportional “revolutions per minute” (RPM) between the left and right wheels.

The differential comprises four functions: differential cage, differential gear, two output shafts, and two planetary gears. Each feature works differently to provide a safe driving experience. 

When driving off-road:

In this situation, the outer wheels travel a long distance. Therefore, the output shaft should rotate at different speeds. The planetary gears must also rotate at different speeds. This is the only way to balance the speed of these two differential characteristics.

When driving on slippery surfaces:

It is the differential cage that is mainly active this time. The complete gear stays in place. Therefore both the planetary gear and the cage rotate at a proportional speed. Unlike cornering, the left and right wheels rotate the same amount.

A clearer picture for Semi-truck differential work:

Imagine cornering a semi-truck to get a clear idea of ​​how the differential works. The outer wheels and inner wheels move at different speeds. A differential distributes torque evenly to each wheel. These differentials resist the inner gears, so the outer gears spin less. The less resistance, the faster it spins.

Differentials allow each wheel to move independently. This avoids driving problems and minimizes the risk of accidents.

What are the signs that my trailer truck’s differential is terrible?

The best way to identify a faulty differential is to check for fluid leaks and vehicle noise. Leaks usually originate from axle seals.

Have you ever seen brown liquid on the ground while parking your rig? 

Well, that could be a sign of a bad diff. In addition to punctures, if it is difficult to turn, there is a high possibility that the differential is damaged. Difficult handling of the tractor/trailer can lead to severe accidents.

Any abnormal noises your vehicle makes can also indicate a faulty differential.

Noise is the most common symptom but is often confused with normal vehicle sounds.

If you hear a ‘whining’ or ‘rumbling’ noise, it’s usually a worn or loose bearing. However, a “clicking” sound may be due to a lack of lubrication or improperly aligned gears.

Can you fix a broken differential on a semi-trailer?

Differentials have several types of damage. However, most repairs fall into two categories. Differential replacement and seals. In most cases, the differential can fail due to wear. However, regular lubrication and proper maintenance can extend its life. You need a mechanic to fix this problem. This process may take 3-5 hours.

Differentials will leak if their pistons and sides are not sealed. This type of repair is demanding and time-consuming. You will have to remove the axle shaft and replace the old seal with a new one.

How much does a Semi Truck Differential repair cost?

Prepare a lot of money for your poor differentiation. If you’re lucky, you can pay between $200 and $400. These are the average and cheapest replacement, repair, and labor costs.

How do you care for articulated heavy-duty truck differentials?

Service your tractor unit differential by soaking it in semi-truck differential oil. Lubrication prevents overheating of bearings and gears.

Oil degrades over time. Therefore, it is necessary to change the liquid from time to time. It is a differential service that replaces the fluid with a new one. The differential case must be removed and resealed before adding clean fluid.