Drivetrain Repair: Driveshaft Axle Differential

Different Types of Drivetrain Repair

u-Joint DriveshaftNo matter what type of vehicle you drive, power will be transmitted from the engine to the wheels through the drivetrain. The drivetrain is made up of a transmission, driveshaft, axle, and differential. Since gears and bearings within these components won’t last forever, it’s likely some drivetrain repair work will be necessary at some point in time.

The key is to minimize the need for drivetrain repair work by keeping the gears and bearings lubricated with the proper amount of clean oil or fluid. The cost of maintenance is a fraction of the cost to repair or replace one of these major components.

Drive axles need grease to keep the CV joint lubricated. Driveshafts need grease inside their bearing caps to ensure they have long life. Universal joints, or “u-joints” as they are sometimes called, are either packed with grease at the factory or require lubrication each time you get your vehicle’s oil changed.

CV Joint Drive Axle Repair vs. Replacement

Your front-wheel drive car has CV joint drive axles that take the engine’s power through the transmission and send it to the front wheels. The CV joint flexes to let your wheels turn even though they are under a heavy load from the engine and weight of the car.

The most common drive axle failures occur when one or both of the rubber CV boots starts cracking due to age. This allows the grease in the joint to be thrown out as the axle spins over time. Without grease in place to lubricate it, the CV joint will start to make a clicking noise heard most often when making a turn.

Repairing boots or joints on a drive axle is usually not cost effective because a replacement axle can be purchased and installed for less than paying a mechanic to remove, repair, and reinstall the existing axle. Remember, CV drive axles have two joints, each with a rubber boot. Even if only one of the 2 boots or joints has failed, the other is worn and will likely fail sooner than later. You will save money required for a second repair by just replacing the complete axle.

Driveshaft Maintenance and Repair

Truck Driveshaft UjointsYour rear-wheel or four-wheel drive car, pick-up truck, or SUV has at least one driveshaft,

possibly two. Driveshafts carry the engine’s power from the transmission to the vehicle’s differential, and then to the wheels.

Maintenance for a driveshaft is only necessary on certain vehicles. When the slip-yoke, CV-joint, or u-joint has a grease fitting, this should always be greased at each scheduled engine oil change service.

The joints will eventually wear out and require replacement. Fortunately, at Wayne’s Transmissions we install only quality replacement joints. In most cases, failure of one joint usually means failure of the second (and third, if present) is close behind. To ensure you won’t find yourself back in the shop for additional driveshaft repair work, we replace all joints when one joint fails.

Common indications of driveshaft problems can present themselves in the form of:

  • Clunks during shifts
  • Shaking while driving
  • High pitched noises

The best way to save money on driveshaft repair is to have a problem diagnosed as soon as you become aware of it. Waiting could result in additional damage and more expense. Find out from your repair professional if the joints on your vehicle have grease fittings. If so, ask whether these joint fittings are greased each time your vehicle has an oil change service performed. New or inexperienced lube mechanics may not be skilled at identifying these grease fittings and may miss them. Going over the repair order with the service provider should verify this is identified as completed.

Differential Fluid Service

Differential services usually fall under the manufacturer recommended 30/60/90 thousand mile change intervals. An adjustment may be called for when towing or hauling heavy loads. Under these conditions, internal metal parts experience increased wear which results in more metal fragments being deposited into the circulating oil. Additionally, the higher temperatures generated by the increased load will degrade the oil more quickly and reduce its lubricating properties.

Differential fluid service involves replacing the old fluid with new fluid that meets or exceeds the manufacturer standards. Since some vehicle differentials have positive traction clutches or locking internal mechanisms, special fluids or additives may be needed. On newer vehicles, synthetic fluids that lubricate better and last longer may be required.

Some repair shops recommend upgrading from standard gear oil to synthetic oils. If you routinely haul heavier loads, this can be a good option to extend the life of the internal components in your differential. While the cost of these oils is usually more than standard oils, they last longer which evens out the increased expense over time.

The most important thing to remember about having your differential serviced is this; following the recommended interval for this service performed can reduce the likelihood of needing major differential repair down the road.

Differential Repair

Leakage of differential fluid is the main cause of failures that require differential repair work. Oil seals and gaskets keep fluid inside the gearbox where lubrication of internal components is critical. If the fluid gets too low, bearings or gears can be damaged and any of the following symptoms may appear:

  • Clunking with acceleration or deceleration
  • Grinding or clunking noises on turns
  • A whining noise that may vary with speed and load
  • Clunking when shifting

While differential repairs like seal or gasket replacement are usually not very expensive, they can run in the $100 to $200 range. Major repairs, like bearing or gear replacement can cost between $1000 to $3000 dollars, depending on vehicle size and manufacture.

As with most automotive drivetrain components, the key to maximizing their performance and life is by keeping lubricating oil at the proper level and replacing it at the manufacturer recommended intervals.

With over 46 years serving the Boise community, Wayne’s drivetrain repair shop specializes in drive axles, driveshaft, and differential service and repair.