DRIVETRAIN SERVICE

COMMON DRIVETRAIN QUESTIONS

• What is the drivetrain and what does it do?

  The drivetrain is the system that takes power from the engine and delivers it to the wheels. It includes the transmission, driveshafts, differentials, axles, and CV joints. On a rear-wheel drive truck, the drivetrain runs from the transmission back through a driveshaft to the rear axle. On an all-wheel drive vehicle, it splits power between the front and rear axles through a transfer case. When any part of that system wears out, the vehicle loses the ability to transfer power efficiently, which shows up as vibration, noise, or handling issues.

• How do I know if my drivetrain or my tires are causing vibration?

  This is one of the most common diagnostic questions we get. Tire-related vibration typically starts at a consistent speed and can often be resolved with balancing or rotation. Drivetrain vibration tends to be more directional: it gets worse under acceleration or deceleration, changes when you shift into or out of four-wheel drive, or comes with a clunking sound that tires don't produce. If balancing and rotating your tires didn't fix the vibration, the drivetrain is the next place to look.

• How often should drivetrain fluids be changed?

  Most manufacturers recommend differential fluid every 30,000 to 50,000 miles and transfer case fluid on a similar interval. Transmission fluid typically runs 30,000 to 60,000 miles depending on the vehicle and use. These intervals shorten significantly for vehicles that tow, go off-road, or operate in extreme conditions. In our experience, drivetrain fluid is the most commonly overlooked maintenance item on trucks and SUVs, and neglecting it is one of the leading causes of premature drivetrain failure.

• My four-wheel drive is making a grinding noise when I engage it. What's wrong?

  A grinding noise when engaging four-wheel drive typically points to a problem with the transfer case, the front differential, or the locking hubs on older trucks. It can also happen when four-wheel drive is engaged on dry pavement, which binds the drivetrain and causes noise and wear. If the noise happens regardless of surface conditions, have it inspected. Transfer case issues that get ignored tend to escalate quickly and become significantly more expensive to repair.

• Can I drive with a leaking differential?

  It depends on how much fluid is leaking and how quickly. A minor seep that's been there for a while is different from an active leak that's dropping fluid on your driveway. If the differential runs low on fluid, the gears and bearings inside run dry and fail fast, sometimes within miles. If you notice a fluid leak under the rear of the vehicle or near the front axle, get it inspected before driving it long distances. A seal replacement is significantly cheaper than a differential rebuild.