The transmission shaft is one of the most important components in a car’s transmission system.
The main function of this part is to connect the engine to the wheels, transforming rotation into actual movement. When it fails, signs such as noise, vibration, or difficulty changing gears appear.
This article explains what it is, how it works, the symptoms of failure, costs, and the best way to act in the event of a breakdown.
What Is The Transmission Shaft?
The transmission shaft, also known as the drive shaft, is a mechanical component that transmits power from the engine to the wheels.
In the traction system, it connects the differential to the wheels (in the case of the rear axle) or the gearbox to the differential (in rear-wheel drive vehicles).
It is crucial for converting engine power into motion.
How Many Axles Does A Car Have?
Most cars have two axles: one at the front and one at the rear. Each axle connects two wheels and supports the weight of the vehicle.
In the case of four-wheel drive vehicles, both axles are needed to move the car. Heavy vehicles can have three or more axles, depending on the number of wheels and the load they carry.
What Is The Transmission Shaft For?
Its function is to transfer torque and rotation from the engine through the gearbox and differential to the wheels. Without it, the car would not move.
The shaft also supports part of the vehicle’s weight and withstands forces generated during acceleration and cornering.
What Are The Components Of A Transmission Shaft?
The transmission shaft consists of:
- Main shaft: the metal tube that transmits torque;
- Constant velocity joint/universal joint: allows flexibility and angles;
- Drive shaft case and bellows: prevent lubricant leakage;
- Supports (bearings): secure the shaft to the chassis and reduce vibrations.
How Does The Transmission Shaft Work?
The transmission shaft works together with its components so that when you press the accelerator pedal, power passes through the differential, enters the axle, and reaches the wheels with the rotation converted into driving force.
What Is The Average Life Span Of A Transmission Shaft?
Under normal driving conditions and with proper maintenance, the transmission shaft can last 200,000 km or more.
However, damage to joints, lack of lubrication, or use on rough terrain will reduce its service life.
Does A Damaged Transmission Shaft Affect Fuel Consumption?
Yes. The slack or resistance generated by the transmission shaft causes energy waste, forcing the engine to work harder and increasing fuel consumption.
What Are The Signs Of A Bad Drive Shaft?
When the transmission shaft is broken or damaged, the main symptoms that arise are:
1. Noise In The Transmission
A metallic noise or clicking sound when accelerating or decelerating may indicate wear on the joints or bearings.
2. Vehicle Vibrations
If you feel vibrations or shaking, especially when cornering or accelerating, this is a sign of possible transmission slack or misaligned axles.
3. Difficulty Shifting Gears
Synchronization problems or noises when shifting gears may indicate anomalies in the transmission shaft.
4. Fluid Loss
If there is visible oil on the axle, this may indicate a damaged joint or broken seal.
5. Loss Of Power Or Car Not Responding
The absence of movement despite the engine running indicates that the car’s axle is broken.
Can I Drive With A Bad Drive Shaft?
Yes, but only for short distances and in emergencies.
Driving with a damaged transmission shaft impairs stability and increases the risk of total failure, which may leave the vehicle immobilized while driving or cause accidents.
How Much Does It Cost To Replace A Transmission Shaft?
If the fault cannot be repaired, you will need to buy a new transmission shaft.
On average, the price of a transmission shaft varies between hundreds and thousands of euros, depending on the category and model of the car.
What Maintenance Should Be Performed On The Transmission Shaft?
In order to avoid future problems with the transmission shaft, you should have the checks scheduled by the manufacturer carried out by your trusted mechanic. There are other recommendations that should be taken into account by the user, such as:
- Transmission oil change: this should be done every 50 to 60 thousand km;
- Tire condition: tires in poor condition overload the transmission system. Therefore, it is essential to keep them in good condition;
- Avoid excessive loads: reducing the strain on the vehicle extends the service life of the transmission shaft.
As you can see, knowing how to identify these problems, performing preventive maintenance, or opting for the correct replacement ensures safety, cost savings, and longevity for your car.
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It was helpful when you said that you could have an oil leak if you notice a burning smell. My husband was talking about how he has been noticing a burning smell in his car for the past couple of days. I’ll pass this information along to him so that he can look into taking his car to auto services for repairs.
Dear Kate,
Appreciated your feedback, and we are happy to help.
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