The short answer is generally no, you should not use tow/haul mode when driving with an empty trailer. While it won’t immediately damage your vehicle, engaging tow/haul mode with a light or empty load offers no benefit and can negatively impact fuel economy and potentially increase wear and tear on certain components.
Understanding Tow/Haul Mode
Tow/haul mode is a feature in many modern vehicles designed to optimize performance and safety when towing heavy loads. It achieves this through several key adjustments to the vehicle’s operating parameters. Understanding these changes is crucial to grasping why it’s typically not beneficial for empty trailers.
How Tow/Haul Mode Works
- Shift Point Adjustments: Tow/haul mode alters the transmission’s shift points, holding gears longer at higher RPMs. This provides more power for acceleration and climbing hills, preventing the transmission from constantly “hunting” for the right gear, especially under load. It also downshifts more aggressively when decelerating.
- Throttle Sensitivity: It often increases throttle sensitivity, meaning the engine responds more quickly to accelerator pedal input. This offers more immediate power when needed for towing.
- Engine Braking: Many systems enhance engine braking, helping to control the vehicle’s speed, particularly on downhill slopes. This reduces reliance on the vehicle’s service brakes and minimizes brake fade.
- Torque Converter Lockup: Tow/haul mode frequently locks the torque converter more frequently and at lower speeds. This improves efficiency and reduces heat buildup in the transmission when towing.
The Problem with an Empty Trailer
The key issue is that an empty trailer doesn’t require the increased power, aggressive shifting, and enhanced braking provided by tow/haul mode. Activating it in this scenario results in several drawbacks:
- Reduced Fuel Economy: Holding gears longer at higher RPMs consumes more fuel. The vehicle is essentially working harder than necessary, leading to a noticeable decrease in MPG.
- Rougher Ride: The more aggressive shifting can create a jerky or uncomfortable driving experience, especially on smooth roads.
- Increased Wear and Tear (Potentially): While the effect might be minimal, constantly operating at higher RPMs and with more abrupt shifts could marginally increase wear on the engine and transmission over extended periods.
When Might Tow/Haul Mode Be Justified with an Empty Trailer
While generally not recommended, there are a few exceptional circumstances where using tow/haul mode with an empty trailer might be considered:
- Extremely Hilly or Mountainous Terrain: If you’re driving up and down very steep grades, even with an empty trailer, the enhanced engine braking could provide added control and safety. However, carefully consider if the increased fuel consumption is worth the benefit.
- Short Distances: For very short distances, the impact on fuel economy and wear and tear will be minimal. The driver might find the more responsive throttle helpful in maneuvering.
Always consult your vehicle’s owner’s manual. It’s the best source for specific recommendations for your make and model. If the manual specifically advises against it, definitely refrain from using tow/haul mode with an empty trailer.
FAQs: Tow/Haul Mode and Empty Trailers
Here are 12 Frequently Asked Questions that will help clarify the subject even further:
FAQ 1: Will using tow/haul mode with an empty trailer damage my transmission?
No, it’s unlikely to cause immediate or catastrophic damage. However, continuous use over long periods could theoretically contribute to accelerated wear on the transmission, though the effect is likely to be minimal. The primary concern is the wasted fuel and potentially less comfortable driving experience.
FAQ 2: Does tow/haul mode affect the brakes differently with or without a load?
Yes. While tow/haul mode typically enhances engine braking to reduce reliance on service brakes, the effectiveness of engine braking is directly related to the weight being towed. An empty trailer offers very little resistance, so the enhanced engine braking will be less noticeable and less effective.
FAQ 3: My trailer is very light. Is that the same as “empty”?
Not necessarily. Even a lightweight trailer has some mass. Experiment. If you notice the transmission constantly hunting for gears on even slightly inclined roads, tow/haul mode might provide a smoother driving experience. However, prioritize testing and observing the vehicle’s performance before making a habit of it.
FAQ 4: Can I switch between tow/haul mode and normal mode while driving?
Generally, yes. Most vehicles allow you to engage and disengage tow/haul mode while in motion. However, it’s best practice to do so on a straight, level road when safe to avoid sudden shifts or changes in engine behavior. Consult your owner’s manual for specific instructions.
FAQ 5: What’s the best way to determine if tow/haul mode is necessary?
Observe your vehicle’s performance. If the transmission is frequently shifting up and down, struggling to maintain speed, or if you feel a lack of control, then tow/haul mode might be beneficial. Pay attention to engine RPMs and fuel economy.
FAQ 6: Does tow/haul mode affect the trailer brakes?
Tow/haul mode itself doesn’t directly control electric trailer brakes. The electric brake controller, if installed, is a separate system that regulates braking force based on the deceleration of the tow vehicle. However, the enhanced engine braking provided by tow/haul mode can indirectly reduce the load on the trailer brakes.
FAQ 7: What other factors should I consider besides the trailer’s weight?
Road conditions, weather, and driving style all play a role. On slippery roads, the more aggressive throttle response of tow/haul mode could make it harder to maintain control. Adjust your driving accordingly.
FAQ 8: Will using tow/haul mode with an empty trailer void my warranty?
Highly unlikely. Tow/haul mode is a designed function of the vehicle. Using it in a way that doesn’t cause demonstrable damage wouldn’t typically void the warranty. However, excessive abuse of any system could potentially affect warranty coverage.
FAQ 9: Is there a difference between tow/haul mode in a gas engine versus a diesel engine?
The fundamental principles are the same, but the specific implementation might differ. Diesel engines often have more low-end torque, so the need for tow/haul mode might be less pronounced in some situations. Again, refer to your vehicle’s owner’s manual.
FAQ 10: Can I use cruise control in tow/haul mode?
Yes, you can typically use cruise control in tow/haul mode. However, be aware that the vehicle will be more aggressive in maintaining speed, especially on hills, which might negatively impact fuel economy.
FAQ 11: What are some signs that I’m putting too much stress on my transmission without tow/haul mode?
Common signs include: frequent and erratic shifting, a “slipping” sensation during acceleration, unusual noises coming from the transmission, and a burning smell. If you experience any of these, consider using tow/haul mode (if appropriate for your load) or have your vehicle inspected by a mechanic.
FAQ 12: If I’m unsure, should I err on the side of using tow/haul mode or not?
Generally, err on the side of not using tow/haul mode with an empty trailer. Start in normal mode and observe the vehicle’s performance. You can always switch to tow/haul mode if you feel it’s necessary.
Conclusion
While the allure of tow/haul mode’s added power and control is tempting, it’s generally unnecessary and counterproductive with an empty trailer. Save fuel, enjoy a smoother ride, and potentially extend the life of your vehicle by using normal driving mode unless specific circumstances warrant otherwise. Always prioritize safety and consult your vehicle’s owner’s manual for tailored recommendations.