Flat towing, also known as four-down towing or dinghy towing, involves towing a vehicle behind a motorhome or another vehicle with all four wheels on the ground. While it's a convenient way to bring a second vehicle on a road trip, it's crucial to understand that not all vehicles are suitable for flat towing. Attempting to flat tow an incompatible vehicle can lead to severe damage to the transmission, drivetrain, steering system, and other critical components. This article will delve into the vehicles that should never be flat towed, providing detailed explanations and guidance to ensure safe and damage-free towing. Understanding these limitations can save you from costly repairs and potential safety hazards.
| Vehicle Type/System | Reason for Incompatibility | Potential Damage |
|---|---|---|
| Automatic Transmissions (Most) | Many automatic transmissions rely on the engine running to circulate transmission fluid for lubrication. When flat towed, the transmission's internal components continue to move without proper lubrication, leading to overheating and eventual failure. Some models have exceptions, but these usually require specific procedures like disconnecting the driveshaft or using a transmission lube pump. | Overheating, burned-out clutches, damaged gears, complete transmission failure, requiring costly repairs or replacement. |
| All-Wheel Drive (AWD) Systems (Most) | AWD systems often have complex transfer cases and viscous couplings designed to distribute power to all four wheels. Flat towing can cause these components to bind and overheat, especially if the system is not designed to disengage completely. Some AWD vehicles can be flat towed if they have a neutral position in the transfer case that fully disengages the axles. Consult the owner's manual. | Damage to the transfer case, differential, viscous coupling, and other drivetrain components. Can result in expensive repairs and potentially leave you stranded. |
| Electronic Power Steering (EPS) | While not directly related to drivetrain damage, some EPS systems can experience issues when flat towed. The system might attempt to compensate for movement that isn't initiated by the driver, potentially leading to overheating of the EPS motor or unexpected steering inputs. | Overheating of the EPS motor, battery drain, potential damage to the EPS control module, and unexpected steering behavior. |
| Vehicles with Air Suspension | Air suspension systems can cause issues during flat towing. The system might attempt to level the vehicle while it's being towed, which can drain the battery or damage the air compressor. Some systems require specific procedures to disable the air suspension before towing. | Battery drain, damage to the air compressor, potential suspension failure. |
| Vehicles with Steering Wheel Locks | If a vehicle has a steering wheel lock that cannot be fully disengaged, flat towing is impossible without modifications. The locked steering wheel will prevent the vehicle from tracking properly behind the towing vehicle. | Inability to steer properly, potential damage to the steering column or locking mechanism. |
| Hybrid Vehicles (Some) | Some hybrid vehicles have complex drivetrain configurations that are not designed for flat towing. The electric motor and regenerative braking systems can be damaged if the wheels are turning without the engine running. Check the owner's manual for specific towing instructions. Some hybrids with specific provisions for flat towing may be towed, but only with strict adherence to the manufacturer's guidelines. | Damage to the electric motor, regenerative braking system, and other hybrid drivetrain components. Can result in very expensive repairs. |
| Vehicles with Integrated Drivetrain Components | Some modern vehicles have drivetrain components that are tightly integrated and cannot be easily disconnected or bypassed for flat towing. Attempting to tow these vehicles flat can cause severe damage to multiple systems. | Extensive damage to the transmission, transfer case, differentials, and other drivetrain components. |
| Vehicles Exceeding Towing Capacity | Even if a vehicle can be flat towed, it's crucial to ensure that the towing vehicle has sufficient towing capacity. Exceeding the towing capacity can damage the towing vehicle's transmission, brakes, and suspension, and can also create a dangerous towing situation. | Damage to the towing vehicle's transmission, brakes, and suspension. Increased risk of accidents due to reduced braking performance and instability. |
| Vehicles with Electronic Parking Brakes | Electronic parking brakes (EPB) can pose a problem if they engage unexpectedly during towing. Some EPB systems automatically engage when the vehicle is turned off, and they may not be easily disengaged manually. | Damage to the parking brake mechanism and the rear brakes. Potential for the vehicle to lock up during towing. |
Detailed Explanations:
Automatic Transmissions (Most): Automatic transmissions rely on a pump driven by the engine to circulate transmission fluid, providing lubrication to the gears and other moving parts. When a vehicle with an automatic transmission is flat towed, the output shaft of the transmission spins as the wheels turn, but the pump isn't operating because the engine is off. This lack of lubrication can cause excessive friction and heat, leading to significant damage. Some automatic transmissions can be flat towed if specific procedures are followed, such as disconnecting the driveshaft or installing a transmission lubrication pump. Always consult the owner's manual and a qualified mechanic.
All-Wheel Drive (AWD) Systems (Most): AWD systems are designed to distribute power to all four wheels, providing enhanced traction in various driving conditions. However, flat towing an AWD vehicle can be problematic because the transfer case and other components are designed to operate with the engine running. When flat towed, the wheels are turning at different speeds, which can cause the transfer case to bind and overheat. This can lead to severe damage to the transfer case, differentials, and other drivetrain components. Some AWD vehicles have a neutral position in the transfer case that disengages the axles, allowing them to be flat towed. Always check the owner's manual for specific instructions.
Electronic Power Steering (EPS): Electronic Power Steering (EPS) systems use an electric motor to assist with steering. When flat towing, the EPS system might detect movement that isn't initiated by the driver and attempt to compensate, leading to overheating of the EPS motor or unexpected steering inputs. While this doesn't directly damage the drivetrain, it can drain the battery and potentially damage the EPS control module. In some cases, it can also cause unpredictable steering behavior, which can be dangerous.
Vehicles with Air Suspension: Vehicles equipped with air suspension systems use air compressors and air springs to maintain a consistent ride height and improve ride quality. When flat towing, the air suspension system might attempt to level the vehicle, which can drain the battery or damage the air compressor. Some systems require specific procedures to disable the air suspension before towing to prevent these issues. Consult the owner's manual for instructions on how to properly disable the air suspension.
Vehicles with Steering Wheel Locks: A steering wheel lock is a security feature that prevents the vehicle from being steered when the ignition is off. If a vehicle has a steering wheel lock that cannot be fully disengaged, flat towing is impossible without modifications. The locked steering wheel will prevent the vehicle from tracking properly behind the towing vehicle, leading to potential damage to the steering column or locking mechanism.
Hybrid Vehicles (Some): Hybrid vehicles have complex drivetrain configurations that combine an internal combustion engine with an electric motor and regenerative braking systems. Flat towing some hybrid vehicles can damage the electric motor, regenerative braking system, and other hybrid drivetrain components because the wheels are turning without the engine running. Always consult the owner's manual for specific towing instructions. Some hybrids with specific provisions for flat towing may be towed, but only with strict adherence to the manufacturer's guidelines.
Vehicles with Integrated Drivetrain Components: Some modern vehicles have drivetrain components that are tightly integrated and cannot be easily disconnected or bypassed for flat towing. Attempting to tow these vehicles flat can cause severe damage to multiple systems, including the transmission, transfer case, and differentials. These vehicles are simply not designed for flat towing, and attempting to do so will likely result in significant repairs.
Vehicles Exceeding Towing Capacity: Even if a vehicle can be flat towed, it's crucial to ensure that the towing vehicle has sufficient towing capacity. Exceeding the towing capacity can damage the towing vehicle's transmission, brakes, and suspension, and can also create a dangerous towing situation. Always check the towing vehicle's owner's manual for the maximum towing capacity and ensure that the combined weight of the towed vehicle and any additional cargo does not exceed this limit.
Vehicles with Electronic Parking Brakes: Electronic parking brakes (EPB) can pose a problem if they engage unexpectedly during towing. Some EPB systems automatically engage when the vehicle is turned off, and they may not be easily disengaged manually. This can lead to damage to the parking brake mechanism and the rear brakes, and potentially cause the vehicle to lock up during towing.
Frequently Asked Questions:
Can I flat tow a vehicle with an automatic transmission? Most automatic transmissions cannot be flat towed without specific modifications or procedures, such as disconnecting the driveshaft or using a transmission lube pump. Consult the owner's manual for specific instructions.
Is it safe to flat tow an all-wheel drive (AWD) vehicle? Most AWD vehicles cannot be flat towed without potential damage to the transfer case and other drivetrain components. Check the owner's manual for specific towing instructions and whether the vehicle has a neutral position in the transfer case.
What happens if I flat tow a vehicle that isn't designed for it? Flat towing an incompatible vehicle can lead to severe damage to the transmission, drivetrain, steering system, and other critical components, resulting in costly repairs.
Where can I find information about whether my vehicle can be flat towed? The best source of information is the vehicle's owner's manual. You can also consult a qualified mechanic or towing professional.
What are the alternatives to flat towing? Alternatives to flat towing include using a tow dolly (with the front wheels off the ground) or a car trailer (with all four wheels off the ground).
Conclusion:
Understanding the limitations of flat towing is essential for preventing damage to your vehicle and ensuring safe travels. Always consult the vehicle's owner's manual and a qualified mechanic before attempting to flat tow any vehicle. By following these guidelines, you can avoid costly repairs and enjoy your road trips with peace of mind.