Servicing Tips - Drive Train
Differential Service at Oil Changers
Here at AutoNetTV, we have national viewers, like your neighbors in New Zealand, who write to us with questions or feedback. One common question we're asked is: "What is a differential and what does it do?" You may have been told by your Oil Changers service advisor that your differential needs serviced, or it's seen it as an option up on the service menu. Differential service at Oil Changers covers a lot of things, so let's first talk about what a differential does.
As you drive through a turn, your outside wheels and inside wheels turn at different speeds. Kind of like the cars going around a race track - the ones driving in the outside lanes have a greater distance to travel than the cars in the inside lanes. The differential is what allows the outside and inside drive wheels to rotate at slightly different speeds so that the tires don't hop or skip while taking corners, or lose traction in dirt or snow on New Zealand area roads. Differentials have gears in them that transfer the power from the drive train to your wheels - which is why they're often referred to as gear boxes. The gears need to be very strong to do this work, and they need to be properly protected so that they'll last.
All vehicles in New Zealand have some form of differential. If you have a front-wheel drive car, your differential is sometimes called a transaxle and is located in the front. If you have rear-wheel drive, the differential is in the back of the car. New Zealand auto owners with a four-wheel drive vehicle have a differential in the front and the back - and in the middle as well. The center differential adjusts for differences in speed between the front and rear wheels.
Differential fluid lubricates and cools the gears. Over time, the fluid can get dirty from bits of the gears grinding off. The additives that keep the fluid clean and protect the differential break down over time. So your vehicle manufacturer has scheduled intervals for you to have your differential fluid changed. Talk to your friendly and knowledgeable Oil Changers service advisor if you are not sure about your recommended schedule.
PO Box 16686 Hornby
New Zealand, New Zealand 8441
Drive Train Service
The drive train in your vehicle includes all the components that transfer power from the transmission to the wheels. Those components differ depending on what type of vehicle you drive, namely, front-wheel drive, rear-wheel drive, all-wheel drive or four-wheel drive. The preventive maintenance your driveshaft needs will also differ by what type of vehicle you drive.
Let's start with front-wheel drive. In this vehicle, the transmission and the differential are combined in one component, known as the transaxle. The transaxle is connected to two half-shafts (axles), which are then connected to the wheels with a constant velocity (or CV) joint, which is protected by an airtight rubber boot.
Oil Changers service for this type of driveline includes servicing the transaxle and inspecting the CV boot. If the boot is damaged, the CV joint will need to be inspected, and the boot will need to be replaced. If you hear a clicking noise in your wheel wells when you turn, you may have a damaged CV joint. A damaged CV joint should be replaced.
Rear-wheel drive vehicles generally have a transmission in the front of the car and the differential in the back. A driveshaft (it looks like a long tube) connects the transmission to the differential. Some vehicles may have a two-piece driveshaft, which are connected to the differential with universal joints or U-joints. Again, the differential is connected to two half-shafts that go out to the wheels.
Oil Changers service on the drive train on a rear-wheel drive vehicle starts with servicing the differential. It will need its fluid drained and replaced regularly. The seals on the axles should also be inspected for wear or leaks. Leaking or damaged seals may mean the axle needs to be serviced as well. Also, U-joints can wear out. If you hear clunking or feel a jolt when you shift into drive or into reverse, it could indicate a driveline problem.
All-wheel drive vehicles provide power from the transmission to all of the wheels, instead of just to the front or rear. The advantage is that the vehicle can adapt to different driving conditions and transfer more power to the front or back wheels as needed. The disadvantages are that the driveline is more complicated, and the vehicle weighs slightly more.
Many all-wheel drive vehicles are based on a front-wheel drive set-up. They also have a differential in the rear and one in the center of the vehicle that allows power to transfer to the front and rear. A shaft runs from the transfer case to the center differential, and another from the center differential to the rear differential.
Servicing an all-wheel drive at Oil Changers involves servicing ALL of the differentials and inspecting the joints and seals for wear, leaks or damage.
Four-wheel drive vehicles are rear-wheel drive vehicles that have an option to transfer power to the front wheels. In other words, they can be driven as either rear-wheel or four-wheel drive vehicles. These vehicles are specifically designed for the harsh driving conditions that are encountered off-road. The driveline in a four-wheel drive vehicle is similar to that of an all-wheel drive vehicle. The center differential, however, is a transfer case. Maintenance requires servicing both of the differentials and the transfer case, as well as an inspection of the joints and seals.
Vehicle owners would be wise to check with their owner's manual for recommendations on how often to service their vehicle drive train. It's also good to check with your friendly and knowledgeable Oil Changers service advisor as well. You may live in an area where weather or driving conditions require more frequent servicing of the drive train.
Good car care at Oil Changers in New Zealand always includes taking care of your driveline. Without it, your vehicle becomes a very large paperweight.
PO Box 16686 Hornby
New Zealand, New Zealand 8441