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A drivetrain (also referred to as powertrain or driveline) is a system which transfers mechanical energy from an engine directly into driving wheels for movement of any vehicle. A drivetrain plays an essential role in vehicle transportation.
Christian Brothers Automotive Queen Creek’s team of ASE-certified technicians can help you understand how your car’s drivetrain works and help make sense of all its components.
Transmission
Transmissions in cars and other vehicles serve to transfer power from engine to wheels through various components such as driveshafts, CV joints and axle shafts.
Transmissions come in both manual and automatic variants and are generally found under the vehicle’s body. They are compatible with engines that produce gasoline or diesel fuel and can also serve to convert their output into usable power for combustion engines.
Modern cars typically use synchromesh transmissions to synchronize input and output shaft speeds; older cars and motorcycles typically utilize non-synchronous transmissions instead.
Current transmission designs incorporate hydraulic torque converters to provide greater engine torque variation across changing engine speeds, leading to greater fuel efficiency in trucks, buses, and other heavy duty vehicles with large changes in acceleration between high and low speeds. This feature can especially benefit vehicles such as school buses.
Some automatic transmissions employ off-axis dual displacement or variable displacement vane pumps with variable operating points to lower operating points and minimize parasitic losses, providing for lower operating points and reduced parasitic losses. These may be an excellent way to achieve high torque performance at lower engine speed as long as they can operate at a lower displacement for most of their drive cycle.
JEGS offers an impressive selection of transmissions and drivetrain hardware to meet the needs of our customers. Our staff are always available to assist in selecting the ideal product for your vehicle.
Driveshaft
A vehicle’s driveshaft is one of the key components in its drivetrain. It acts as an intermediary, transporting torque from its source – such as transmission – directly to its wheels in either front-wheel, rear-wheel or four-wheel drive vehicles.
A drive shaft is a long tube of steel connecting one end of a vehicle’s transmission with its rear axle on the other. It contains U-joints and slip yokes for flexible movement when braking or acceleration occurs, helping it respond appropriately.
Unless the U-joints on your driveshaft remain undamaged, turning your vehicle can become difficult. A worn U-joint can prevent wheels from turning properly, potentially leaving your car vulnerable during turns and leading to loss of control when trying to make turns.
Another telltale sign that your driveshaft is worn out is when it makes noise when moving – whether that be screeching, squeaking or clanking noises as it moves.
Your drive shaft’s center bearing has failed or its U-joints have worn down too much, if there’s shuddering when accelerating from a stop or low speed; or when shifting gears suddenly. These can all be indicators that something’s going wrong with its assembly.
Dismissing these symptoms is key to driving safely and efficiently in your vehicle. The sooner any issues with the driveshaft or its supporting parts are addressed, the sooner your car will function as intended.
Damaged driveshafts can have an enormous impact on the performance of your vehicle, forcing you to work harder and pay more in fuel expenses. They also increase risk for an accident while being costly repairs; so if your driveshaft doesn’t seem like its working properly, take it immediately into a shop for effective and prompt solutions.
CV Joints
CV joints are essential to drivetrain hardware. They allow axles to flex and turn while transmitting power from transmission to wheels. A CV joint consists of a bearing race, balls and cages enclosed within a housing covered by rubber to protect from dirt, moisture and lubricating grease build-up.
As with any mechanical part, CV joints can wear down over time, leading to their eventual failure. This occurs because tight tolerances cause gaps to open between moving parts as they wear down – increasing friction and heat generation from spinning components.
If you hear clicking noises when turning the steering wheel or feel vibrations when accelerating or shifting gears, or experience increasing sounds with each drive, your joints could need some repair. This is particularly true if the sound intensifies over time.
Failure of CV joints is often indicated by their inability to transfer torque between transmission and wheels in an even fashion, potentially endangering control of vehicle while cornering or accelerating.
If this occurs, your front tires could lose contact with the road and you could be vulnerable to an accident. As soon as possible, get your joint repaired to ensure you can continue driving safely.
An effective way to ensure that your CV joint is operating efficiently is to inspect its rubber boots for signs of damage. Outer CV joint boots tend to wear down faster due to more movement. Cracked or split boots allow contaminants into the joint and accelerate its wear out over time.
Axle Shafts
Axle shafts transfer torque from a transmission to the drive wheels on any vehicle, be it front wheel drive or four wheel drive. They are usually constructed out of solid steel to withstand both weight of vehicle as well as rotational forces transmitted from its wheels.
There is a wide range of axles on the market today. Some are standard-designed to meet the needs of many vehicles while others may require special modifications for specific applications.
The various types of shafts for vehicles vary depending on their technical requirements and amount of force needed to transfer power from transmission to drive wheels. Shafts must withstand extreme speeds, acceleration, braking, cornering gradients and various load conditions such as tarmac roads, asphalt surfaces or even off-road action such as rocks gravel sand or mud terrain.
One type of axle shaft design is the semi-floating axle shaft. This design utilizes bearings between the axle casing and hub axle shaft that protect it from shearing or bending forces, protecting its integrity from shear force or shearing forces.
Fully floating axle shafts provide another alternative design option, featuring bearings positioned between wheel flange faces and the shaft to distribute weight more evenly so as to prevent bearings from having to bear all of its weight, unlike in traditional non-floating designs.
Finally, there is the U-joint. This cross-shaped piece connects the drive shaft to the differential assembly in front-wheel drive vehicles and some rear-wheel drive cars with independent suspension systems. It allows your drive shaft to pivot laterally without disrupting other driveline components or breaking down, so your car turns safely.
U-Joints
U-joints are essential components for allowing drive shafts to rotate at different angles, without which their function would be impossible. Without them, the driveshaft would simply not function.
U-joint trunnions pivot on axle yokes and are made from materials such as steel, plastic or thermoplastics. Furthermore, different configurations such as bored, solid hub, keyed hub splined hub or solid hex can also be chosen from.
Universal joints are frequently utilized with yokes on transmissions, gearboxes and drive shafts for use as components that transfer torque in both directions between the U-joints. Yokes allow these connections to bend to accommodate for any angular movements within the driveshaft’s path.
As soon as a car is driven hard, its drive shafts become subjected to rigorous strain, leading to wear-and-tear on their universal joints and an increase in wear-and-tear damage on them. This phenomenon is most visible with front drive vehicles as their drivelines experience angular movement.
Locking differentials and oversized tires exacerbate this issue further by placing extra stress on driveshaft u-joints; when combined, this may cause the c-clips of those joints to come loose from their yoke and break apart completely.
As they rotate, u-joint bearing caps tend to “spin” inside of a yoke as they rotate; without proper C-clip retention mechanisms in place, this could eventually damage its integrity and result in permanent yoke damage.
As this can lead to catastrophic driveline failure and costly repairs, it is recommended to replace your u-joints as soon as they show any sign of wear or failure; or if the driveshaft begins moving at high speeds. A reliable auto repair shop can assist in diagnosing your issue and providing any needed parts.