Regardless of engine power or gearbox type, a car equipped with propulsion or all-wheel drive depends on a key part of the transmission assembly: the driveshaft or Cardan. If conventional traction machines use planetary gears to transmit the driving force from the gearbox to the wheels, the others are based on this axle, also known as a driveshaft. A part that is difficult to repair or recondition, the Cardan shaft has a considerable purchase cost if it needs to be replaced.
In its operation, special importance is given to the perfect balance, for a total lack of vibrations, as well as the best lubrication of the components. Usually, the latter is done on the production line of the subassembly, but it may not be enough for the entire period of use of the auto. In the absence of optimal lubrication, oil leaks can occur, leading to direct friction of metal parts. Any sign that could announce a Cardan fault will have you go immediately to a specialized mechanic. Otherwise, you could face one of the most difficult to repair failures of an all-wheel-drive or propulsion car.
How much does it cost to balance a driveshaft?
The cost to balance a driveshaft depends on your car and the mechanic you choose. Our research shows that professional labor costs about $125-$190, but this varies widely depending on where you go. Also, if you need new U-joints, which are required in most repairs, your bill can come to $220 or even more. For example, if U-joints seem loose or bent and worn down it might be recommended that you get these replaced.
According to a member from the ford-trucks.com online forum, the cost of a complete rebuild and shaft balancing is around $180.
On another forum thread, a member mentioned he paid $200 to replace both his U-joints and balancing the shaft at his Toyota dealership.
The modern-day services might have a computerized driveshaft balancer that is able to balance up to four pieces of the drive shaft depending on its specification. This multi-step process includes checking for tolerances in U joints and tubing while making sure it’s corrected at all times as well. Lastly, the part will be balanced to meet the manufacturer’s RPM recommendation. To ensure a vibration-free drive, weights are often welded onto it.
Important things to remember
A balanced driveshaft is extremely important for a smooth driving experience. The torque from the engine and transmission must be equal to each other, as well as at the same speed at which your car’s driveshaft spins in order to balance it correctly. By balancing your shafts you will prevent any problems that may arise due to an out-of-sync driveshaft or unbalanced driveshaft.
If the RPMs are not stable and reach a certain speed, it may result in the failure of the driveshaft.
Due to the intense stresses to which it is subjected during the use cycle, the Cardan shaft can manifest a whole series of malfunctions. Subjected to high forces of inertia, which produce intense vibrations that can lead to premature wear of shafts and joints, the Cardan shaft can engage the differential and gearbox in the chain of damage. The first sign that you have a Cardan shaft that requires a quick intervention of the car mechanic is the metallic sound that the moving part will produce when starting the car.
How to recognize a faulty driveshaft
A squeak-like noise when starting the engine (either in front or in reverse)
Most of the components that make up the Cardan shaft are lubricated from the factory, but this lubrication may not be enough to support the movements made by the auto while driving, after a certain period.
Given that each element of which the shaft is composed withstands a certain movement, friction, change of speed, it is very possible that this oil evaporates quite easily. Especially since the supported movement is in the same location.
Thus, without any form of lubrication, the friction remains between metal and metal, producing a noise similar to a creak. You can probably catch this noise only when starting or before the car picks up a speed and the sound is attenuated by other related noises.
A chuckle like noise when you change gears in reverse
This specific type of sound indicates that the bearings that form the Cardan shaft have enough space for movement to allow the necessary rotation of the drive shaft, but they reach a neutral point when you try to put the car in reverse.
This may mean that the next stage of wear has been reached, after the one mentioned in the previous point. You must ask a mechanic to lubricate the cardan shaft, but also to prevent other damage.
A certain vibration of the car
Any kind of out-of-the-ordinary vibration or movement when driving a long distance and at high speed is a bad sign.
In this case, it indicates that the bearings have worn out to such an extent that they allow a wider than usual movement of the drive shaft, coming out of its shaft.
Even if the sensation of an unbalanced wheel can be similar, it will be much more frequent, because the rotations of the gear shaft are 3-4 times more frequent than those of the wheels.
The transmission fluid is leaking
The moment you notice that the transmission fluid starts to leak behind the transmission you should know that you have Cardan problems.
It means that the above-mentioned vibration has come to affect the driveshaft and cause damage to the output shaft, thus leading to leakage of the drive fluid.
Loud noises from under the car
When there is a large play between the parts of the cardan, it will make some loud noises, as if you hit two metal hammers head to head or even similar to the sound of the bell.
In this case, the cardan shaft must be changed urgently.