Monthly Archives: March 2017

Replace Drive-Axle Boots

Front-drive vehicles, many all-wheel-drive vehicles and some rear-drive vehicles have constant-velocity joints that connect the transmission to the drive axles and wheels. A front-drive vehicle will have four CV joints, each covered by a boot.

CV joints are covered by rubber or plastic boots that keep the joints lubricated and prevent dirt and water from getting in. If a boot tears, grease can leak out and moisture and dirt can get in. If left unattended, it’s only a matter of time before the joint fails from lack of lubrication or corrosion. When that happens, the whole axle may need to be replaced.

Drive axle boots often last the life of a vehicle and are not listed among items that need periodic replacement. They should, however, be inspected at least once a year, or more often on high-mileage vehicles or ones that see what manufacturers describe as “severe” service, such as off-road use or driving-industry conditions.

If a small tear is caught early, it may require only the relatively minor repair of replacing the boot and adding fresh grease instead of more major surgery. Many repair shops, though, will recommend replacing the entire axle if a boot is torn because there may be unseen damage to the CV joints and axle shafts that could result in other problems.

Belts and Hoses Last

Maybe forever, if you rely on an overly liberal interpretation of the maintenance schedules set by some vehicle manufacturers. That doesn’t mean you should ignore them or even accept the manufacturer’s recommendations, though; instead, add them to your list of items that should be checked annually after the first three or so years of ownership.

With accessory drive belts, most manufacturers recommend only a periodic inspection for cracks, fraying or other visible wear, and on some GM vehicles the first inspection isn’t until 10 years or 150,000 miles, when someone else might own the vehicle.

Hoses? What about them? Most owner’s manuals don’t even mention radiator or coolant hoses (except that they can get really hot on an overheated engine). Other hoses, such as for the power steering or air conditioner, usually are mentioned only as something that should be checked as part of routine maintenance or when leaks are suspected.

Coolant hoses typically last several years, though anything longer than 10 years may be pushing the limits. Rubber weakens with age and from repeated exposure to hot coolant, so the older they get the higher chance they’ll leak and cause the engine to overheat.

Drive belts are usually the serpentine type that snake their way around pulleys to power the alternator, air conditioning compressor, power steering pump and perhaps the water pump, and they’re designed to last several years.

When to replace a drive belt is a judgment call by a repair technician, and it’s up to the vehicle owner to decide if the time is right given the manufacturers have largely chosen to stay out of it. We would err on the side of caution, because when a drive belt breaks your car comes to a halt. Depending on where this happens and when, a belt that fits your car may not be available until tomorrow, leaving you stranded.

Comes to automatic transmissions

When it comes to automatic transmissions, fluid leaks and low fluid levels are probably the most common problems owners experience, especially as a vehicle gets older and parts wear out.

If you don’t notice a puddle of transmission fluid (often red, but sometimes other colors or clear) on your garage floor or driveway, you might observe that the transmission is slow to engage a drive gear or shifts sluggishly into higher gears while you’re underway. Both are signs that the transmission fluid is low, which usually can be traced to a leak, though other issues could be at fault. Transmission fluid also can wear out over time and may need to be replaced.

Other warning signs include unusual noises, such as a whine or a buzz, shifting harshly into the next gear instead of engaging smoothly, or slipping out of a gear while driving. If you hear a grinding noise from the transmission, that could be because bearings have failed, allowing metal-to-metal contact between parts that aren’t supposed to rub against each other.

Some vehicles have transmission-warning lights that illuminate when computers sense a problem, but on many cars, the transmission is linked to the same computer that controls the engine, which is the powertrain control module. That could result in the check engine light coming on when you have a transmission issue.

Using your car or truck for towing or hauling heavy loads makes the transmission work harder and can cause it to overheat. Often that will trigger a warning light; if you smell something burning, that could be an overheated transmission. Cars, trucks and SUVs that do a lot of towing or heavy hauling may need what’s called auxiliary transmission fluid cooler.