Monday, May 3, 2010

Tips for Towing Disabled Vehicles
Sophisticated new vehicles require great care and different types of towing techniques.

By Ann Job of MSN Autos

Click to enlarge picture

Always make certain that the tow truck driver knows the proper way to tow your vehicle.

On occasion, our car, van, truck or sport-utility vehicle can break down and need to be towed.

Decades ago, it wasn't uncommon to see a friend, family member, neighbor or Good Samaritan towing the stranded vehicle home for a needy driver.

It's rare to see this today—for good reason.

Towing practices, like today's vehicles, are more sophisticated than they were years ago— so sophisticated, in fact, that there are more rules and "don'ts" than ever before.

Even AAA, the largest member-supported roadside assistance service in the United States, offers a towing manual for tow truck operators that has "more than 350 pages of details involving every make and model," said Larry Keller, editor at AAA of Michigan.

As each year progresses, AAA sends out further towing news via service bulletins, Keller said.

So, no, towing isn't a simple procedure where someone throws a rope or chain around a car's front bumper and "tows" the vehicle home.

In fact, if there's one key thing to remember about towing, it is that you should always follow the owner's manual and make sure your tow truck operator does, too. If he refuses to do so, find another tow truck.

Otherwise, you can face the risk of damage to your vehicle.

Safety Considerations
These days, there is much more emphasis on safety in towing, with the realization that there's a potential for injury or even death during towing maneuvers.

For example, in the early 1980s, a Good Samaritan driver was killed in the Upper Peninsula of Michigan when he attempted to tow another driver out of a snow bank.

The man died when the chain he had attached to the other vehicle broke and the loose end flew into the back window of his truck cab, striking him in the head.

There are other towing dangers, too.

Do-it-yourself towed vehicles don't have lights and flashers that tow-truck drivers use to alert other drivers that they're approaching a disabled car. So other drivers can come up quickly at the back of these vehicles-in-tow and rear-end them, since they typically aren't keeping up with traffic.

Chris Matthews, an Automotive Service Excellence-approved technician and coordinator of the AAA-approved auto repair program, pointed out that brakes on a DIY-towed vehicle typically are crippled as well because with the vehicle's engine not on, there's no vacuum boost to help the brakes work normally.

Thus, if the vehicle that's pulling a disabled car stops suddenly, it's likely the towed vehicle won't be able to stop in time to avoid rear-ending the tow vehicle.

Steering can be another problem, with so many of today's vehicles featuring power-assist steering systems, not to mention steering wheel locks. Note that when the engine is not operating, there is no power assist, so attempting to steer a towed vehicle requires substantial extra effort.

Avoiding Mechanical Damage
Vehicle owners also should want to make sure their vehicles aren't damaged during towing.

Each owner's manual provides specific instructions and warnings for each vehicle and should be strictly followed.

Subaru spokesman Rob Moran, for example, notes that the owner's manuals for all new Subaru Forester, Legacy and Impreza models—basically every Subaru with standard all-wheel drive—tell drivers that all four wheels need to be off the ground when a Subaru is towed. This is also known as flat-bedding.

Otherwise, "you could get damage to the transmission or differential," he said.

Matthews explained because all four wheels get power and are therefore "tied together," there's really no way to put any of the wheels to the ground and not have the transmission or transaxle "burn up."

The reason? Simply, as any of the drive wheels moves while the vehicle is improperly towed, mechanicals in the transmission and sometimes in the differential move, too. Since the engine isn't operating, there are no fluids flowing to keep the parts lubricated.

The Cadillac Escalade with all-wheel drive has caused special problems in towing, Matthews said.

The Escalade AWD can't be pulled behind a tow truck, but must be flat-bedded for the same reasons described for Subaru vehicles.

Since an Escalade AWD weighs more than 5,500 pounds, a medium-duty flat-bed truck is required, and "they're hard to come by as a lot of [roadside service companies] may not have them," Matthews explained.

Cadillac engineers are working on a solution, he added.

Front- and Rear-Wheel-Drive Vehicles
Lubrication is an issue in rear- and front-drive vehicles, too, and draws attention to the need for tow-truck operators to be skilled in different towing procedures.

For example, the Mazda RX-8 is a rear-wheel-drive car and "should have its rear wheels off the ground" if it's being towed, according to the owner's manual.

By keeping the rear wheels, which are the wheels that receive power via the transmission and driveshaft, immobile and off the ground, there's no moving of the linked parts and thus, no lubrication issues.

In contrast, a front-wheel-drive car is generally OK to tow with its front wheels off the ground for the same reason, Matthews said.

In this case, the front wheels are the drive wheels connected to driveshaft and transmission and so need to be kept immobile during towing.

Beyond the driveline issues, owners of vehicles with lowered chassis and sport-body appearance kits should be sure tow truck operators take extra care to ensure the spoiler, lower body kit pieces and/or undercarriage aren't damaged as a vehicle is raised and lowered onto a truck.

Other Towing Insights
You might wonder, then, just how RV owners manage to flat tow vehicles behind their large mobile homes.

Actually, I've long wondered why I see so many Saturns towed behind big RVs.

Sue Holmgren, Saturn spokeswoman, had the answer. In fact, she said lots of RVers know that Saturns are easy to flat tow, and typically don't require major modifications, such as a lubrication pump or driveline disconnection, before towing.

Specifically, all Saturn S-Series and L-Series cars, even with automatic transmissions, and all Ions and VUEs with manual transmissions can be flat towed. Owners must follow instructions in their manuals. But RVers take note: L- and S-Series Saturns are no longer in production.

Automatics tend to be more problematic. Holmgren noted the S- and L-Series Saturns have automatics with bearings, which require less lubrication than do automatics on some other cars that have bushings or thrust washers.

In addition, "the input shaft into the torque converter needs to be able to rotate freely," which is what these Saturns have, she said.

Generally, a vehicle can be flat towed as long as the transmission internals are not turning. Thus, an SUV trailing behind a big RV most likely has had its driveshaft disconnected from the transmission.

Bottom line: It is critically important that vehicles be towed according to the owner's manual instructions.

Ann Job is a freelance automotive writer.

No comments:

Post a Comment