The differential allows the drive wheels in your 2 Wheel Drive (2WD) or 4 Wheel Drive (4WD) car, truck or SUV to turn at different speeds. Proper lubrication of these differential gears is imperative for the safe and optimum performance of your vehicle. Checking the rear differential fluid every 15,000 miles for a "gummy" consistency will prevent costly repairs and can even extend the life of your drive-wheel tires.
Differential and Transfer Case services are recommended every 15,000 miles. Fluid breaks down, and gets contaminated with dirt that can damage bearings and gears in your front and rear axles, affecting driving and performance in your car or truck. Dan explains the importance of regular differential and transfer case services in this video.
Automatic transmission fluid also serves as a coolant-like the anti-freeze in your car radiator- to keep the transmission parts from overheating, and transmits power from the engine. Regular servicing will give your transmissions longer life, keep shifting smoother, and boost performance.
Car owner manuals vary considerably about when to change transmission fluid-from 30,000 to 60,000 miles. They all have one thing in common though: they don't account for how or where you drive. Severe driving conditions means the fluid will break down sooner.
What are severe driving conditions? Driving in Salt Lake City, and throughout Utah.
Spending hours in commuter traffic;
Hauling heavy loads (boats, trailers, towing);
Driving in Utah, where the temperatures go below freezing, and soar over 100 degrees. Driving in and around Salt Lake City and Utah, changing your transmission fluid may come at 30,000 miles, or sooner, with a combination of the above factors.
Check for driving symptoms, and transmission fluid color and odor.
If your car shifts gears with a lag or a lurch, or is "mushy" or takes extra time to shift on cold mornings, it's time to check the transmission fluid.
Fresh automatic transmission fluid (or ATF) is bright red and has a slightly sweet petroleum smell. If your dipstick level is below full and the fluid is brown, or dark and smoky with a stench of burning (or smells like cheap perfume), it needs changing immediately---and damage may already been done.
Automatic transmission fluid that is reddish brown, without a pungent odor, tells you that it is time for a fluid change.
If there's a pool of fluid underneath your car, it could be transmission fluid leaking out of the cooler line that runs to the bottom of the radiator. Get it fixed and top up the fluid.