The Basics of Towing With Your Diesel (plus, the basic parts you’ll need)

One of the biggest reasons why people buy a diesel truck is for its towing and hauling capability. If you have a trailer attached to your truck, the massive amount of torque these engines produce will make it easier to climb hills, take off from a stop light and even maintain speed with a massive head wind, and generally they will burn less fuel when doing the same amount of work as a gasoline engine. If you walk through the showrooms today and ask about max towing capacity from the biggest dual-rear wheel pickups each manufacturer offers, you’ll be amazed to find Ford, Ram, and GM all offer pickups which can pull north of 35,000 pounds when properly equipped with a diesel engine, but the gas powered equivalent will have a disadvantage in terms of weight rating. While it’s nice to be able to haul the equivalent of almost eight passenger cars at once, the hefty price tag of a brand new Dually can be a bit steep, especially if you tick the “Limited” box at your local Ford dealer. You can spec out an F-450 SuperDuty to almost a hundred grand, which is kind of ludicrous, especially if you consider the difficulty you’ll have finding a parking spot. If you need that much towing capacity however, there is no substitute for a crew cab long bed 1-ton dually, but the most popular configuration of truck over the last 10 years without question is the 3/4 ton crew-cab short-box single rear wheel pickup. Generally, the trade-off is a slightly lower towing capacity, but today even the 2500s have a tow rating which is approaching 20k lbs.

Regardless of which kind of truck you have, there are a few extra parts you will need in order to hook up to a trailer and safely pull it down the road, so today we’ll cover the fundamentals of towing and hauling equipment. While it might seem like basic information, everything from different types of trailer attachments to positioning your load on the trailer, and even how to properly tie it down are all very important pieces of information to know. Once we’ve laid a strong foundation, next time we can cover the fun stuff like adding power for even better performance and efficiency while towing.

Attaching the Load

The most common type of trailer you will see on the road behind a pickup is what I refer to as a “bumper pull”, but despite the name it doesn’t actually connect to the bumper like they did in the old days. Instead, all modern trucks come with a receiver hitch which is a heavy structural part bolted directly to the rear of the frame, and in the center just below the license plate is a square slot for you to insert the hitch of your choice. Depending on the height of your truck and trailer, the hitch may need to be raised up or lowered down, and there are many types of hitches to work for every combination, even if your truck is lifted and rolling on 40’s or bagged and laying its frame on the ground. Most stock height 3/4 or 1-ton trucks can get away with a simple 3” drop hitch with a 2.5” square shank, and a standard fixed-height hitch like the Reese Class V is a great place to start. It is certified to haul a trailer with a tongue weight of 2,000lbs and a total weight of 18,000lbs, which is near what most 2500HD series trucks are rated to pull.

The only drawback to a traditional fixed-height hitch is they are a bit cumbersome to swap around if you have multiple trailers with different tongue heights or hitch-ball sizes. While in theory it should be simple to un-bolt one ball and swap it out for another, most of the time the nut is extremely tight and a little rust may have built up, and when it’s time to swap the ball out, you might not have the tools you need on hand. While you could simply buy a few extra hitches and set one up for each of the trailers you haul, that cost can add up in a hurry, so instead it would be wiser to have one hitch to rule them all. The most popular adjustable drop hitch on the market today is the Gen-Y Hitch, and they have many different variations. Their basic Mega-Duty series hitch can drop either 6”, 9”, or 12”, and comes with a reversable ball with both 2” and 2 5/16” sizes. The 2.5” shank version is rated to pull a hefty 21,000lbs, plus the design will also work with an equipment trailer with a round pintle hitch. If you haul on rougher roads with a bumper pull, you will notice a lot of jarring and bouncing is transferred from the trailer into your truck which is very annoying and uncomfortable. Another innovative hitch from Gen-Y will reduce the motion transfer from trailer to truck by 90%, and that’s “The Boss” Torsion Flex hitch. It uses a pair of rubber pivots to isolate the truck and trailer making for a smoother ride, but because it eliminates bouncing, it can even improve braking distance on rough surfaces.

If you like your trucks taken to the extreme in terms of height but still want to tow, you’ll need a hitch that will drop down a bit more than usual, and Gen-Y has you covered there as well with options of up to 21” of drop. Because the ball is so much lower than the receiver at that level, a twisting force is applied to the hitch which can cause metal fatigue and a failure. To prevent this, the longer drop hitches also include stabilizer links to prevent the hitch from twisting during acceleration or braking.

Gooseneck: While a bumper pull trailer leaves the bed of your truck free to use for other cargo, there is a point where the tail starts to “wag the dog” as the trailer weight increases. Even if you have the weight of your cargo properly distributed (more on that later), by having the hitch several feet behind the rear tires, you create some instability in the truck. The more weight you place on a receiver hitch, the more the front steer axle of the truck is lifted up, which in extreme situations can lead to a loss of steering or braking. To combat this, usually the heavier trailers you see will have the hitch mounted slightly in front of the rear wheels. While the majority of the tongue weight will be supported by the rear tires, a slight portion is transferred down on the front axle instead of lifting it, making for a much more stable combination.

A gooseneck coupling is very common on enclosed cargo and flatbed trailers, horse trailers and more, and its name refers to the shape of the front structure which raises up and over the tailgate, since the shape resembles Canada’s favorite flying rodent. Every gooseneck trailer in the USA attaches to the truck using a 2 5/16” ball, and whether it came equipped from the factory or was installed later, there is a heavy framework which sits just below the surface of the bed, and only the ball protrudes through the floor, along with some connections for safety chains.

5th Wheel: While some people use the terms interchangeably, a gooseneck and 5th wheel aren’t even close to the same thing. A 5th wheel trailer has a kingpin attachment and are most commonly found on a camper or toy-hauler. Where a gooseneck ball sits a couple inches above the floor, a 5th wheel hitch is about a foot high, and can have a footprint of about 2’x2’. If your truck came from the factory with no 5th wheel prep package, it does require some work to mount the attachment rails to the frame, but if you have a later model truck like the 2020 GM HD’s, a hitch like the Curt E16 can install in minutes to the puck connectors already built into the truck, and when you’re done hauling, the hitch is easily removed and you have all of your bed space back.

Stopping the Load

Once you have your trailer hooked to your truck, the next obstacle is slowing things down. Most single-axle trailers with a capacity of 4,000lbs or less rely on the brakes of the truck to bring things to a safe stop, but once you throw a car or piece of construction equipment onto a heavier flatbed, the service brakes of the truck will no longer be able to scrub off the speed, so there are a few extra measures you can take. All larger trailers will have electric brakes fitted to at least one of the axles, but they rely on commands from your truck to tell them when to apply. Just about every new truck will have a trailer brake controller already built in when they leave the assembly line, but a lot of older trucks did not. The aftermarket has plenty of options available however, and the Tekonsha P3 is a great and inexpensive way to slow down your trailer. The brake controller connects to the wiring circuits under the dash so the controller knows when you step on the pedal, and it applies the trailer brakes accordingly. There is also a gain adjustment which compensates for the weight of the cargo on the trailer, so you don’t lock up the brakes when un-loaded or have insufficient pressure with a heavier load.

Supporting the Load

A larger trailer can put a literal ton onto the back of your truck, and that much weight will cause even the toughest springs to compress and the back end to sag. An F-450 might not notice so much, but the more popular F-250 or Chevy 2500HD may need some extra help to keep the axle off the bump stops. In the past, the first upgrade an RV shop might sell you would be an add-a-leaf or overload spring, which puts more leaf springs in the pack to increase its spring rate and capacity. While that will accomplish your goal of less squat, the side-effect when the truck is driving around empty is a very harsh ride. Most drivers are trying to achieve the opposite, so instead the solution is to add an adjustable spring which can be turned on and off whenever you need it, and that’s an airbag.

When most people think about an air spring, the first thing that comes to mind is a lowrider or show truck which lays the rockers on the ground, but they have a lot of practical uses in a heavy-duty application as well. A kit like the PacBrake AMP AirBag attaches between your truck’s axle and the frame with the included brackets, and as you fill the bags with air pressure, they will push the rear end of the truck back to its normal height, and when you are driving unloaded, you can simply release the air pressure to restore your smooth ride quality of your stock leaf springs. There are two methods of filling the air: the first is with a Schrader valve which is exactly the same as pumping up your tires, or if you want adjustment on the fly, you can upgrade to a full on-board air system with controls inside the cab which allow you to air up and down in just seconds.

Securing the Load

Once you have the trailer hooked up and the truck sitting level, you need a way to attach the cargo to the trailer, so it doesn’t fall off. Most heavy equipment like a Skid Steer or back-hoe will require the use of heavy chains and binders, but most folks who are reading this will more likely be securing a UTV, ATV, or a car to their trailer. A more manageable option is some synthetic ratchet straps, and no name is better known than MAC’S. Their Ultra Tie Down Kit comes with a set of four ratchet straps, four axle straps to loop around the frame or axle, and a handy duffel bag to store it all when not in use. They come in six- or eight-foot lengths, and they can safely hold a 10,000-pound object in place.

Balancing the Load

The very last point worth mentioning is how to properly balance the load on a trailer. The rule of thumb states you need about 10 to 15% of your trailer’s total weight on the tongue, so if you have a 10,000lb trailer, that means you need between 1,000 and 1,500lbs on the hitch. The simplest way to gauge position is to drive up onto the trailer until the cargo is centered over the trailer tires, and then move forward a bit further until the back end of the truck squats roughly level with the front, but you can get a bit more scientific. A cool product from Weigh Safe will tell you exactly how much tongue weight is on your truck, because it’s a Drop Hitch assembly with a small scale built into the side.

Moving the Load

When you are hauling with your diesel, remember to follow the manufacturers weight ratings for both your truck and the trailer you’re hauling, and never overload your rig. Also, keep in mind that just because the salesman said your truck is rated to tow a 35,000lb trailer, doesn’t mean you are legally allowed to operate it at that weight without the proper license. Regardless, if you follow these few simple guidelines and take care to properly hook up and load your trailer, you’ll be on the right path to success. Towing with a stock diesel can be a fun experience, but once you add some upgrades into the mix, you can transform how your truck hauls, ensuring you’ll be first to the top of the hill. Next time we’ll cover how a few key modifications to the turbocharging system and chassis can make all the difference, so stay tuned!