Using a Semi-truck as an RV Hauler

By Jack Mayer

Shown here are the three common models of Volvo’s that are converted to RV Haulers. The leftmost truck is a Volvo 780. In the middle is a Volvo 670, and on the far right is a Volvo 730. Not shown is a 630 – which is the same height as the 730, but has the shorter condo of the 670. The 630 and 670 are the same cab, except the 670 is full-height. That gives you more interior storage. The 780 and the 730 have a wider cab, deeper (longer) condo. The 780 has the most storage and most “livability” of the three.
The 670 has two bunks in it, as does the 780. The 670 is the most common Volvo and is widely used by long-haul fleets. The 780 is mostly an owner/operator truck, and the 630 is mostly a regional hauler truck. You see the 630 pulling tankers and flatbeds.
The 730 is the rarest of the four trucks.

But It Is So Big!!!

Some people are intimidated by the size of a semi-truck (HDT, or Heavy Duty Truck). Our Volvo 610 (the white truck on the left in the above photo) was a short wheelbase conversion, measuring 182 inches. The wheelbase is just a little over what a crew cab dually pickup truck wheelbase is (6” more), and the total truck is just a few feet longer. With the fifty degree Volvo wheel-cut (how far you can turn the wheels) you can maneuver far better than any pickup.  And, although the truck is taller than a pickup, the 10’ 10” is still low enough to drive around town and into neighborhoods.  You do have to be aware of low tree limbs, and you will not be going through most drive-thru’s, but it proves not to be much of an issue.

2009 Volvo 780 configured as a car-hauler.

The bottom line is that the “footprint” of that truck on the road is about the same as a crew cab dually, and it maneuvers better. Yes, it is a little taller. But it is the same width as the crew cab rear wheels, and easier from a driving perspective because the front is the same width as the rear – unlike the pickup, where the rear is wider. On the pickup, you don’t visually “see” that extra width out in front of you, so it is harder to adapt to.

In the case of our 780 – the larger silver truck shown with the car on it – it is definitely larger than a pickup at 29’ 3” overall length. But it has a condo you can live in and a car on the deck. Because we carry a car on the 780 the truck itself is not a daily driver, so the additional size of the truck is not really a factor in livability.

Visibility to the rear is also a concern we hear from people. It is true that you do not have windows to look out of to the rear. But the mirrors are so big that this mostly negates the issue. And the fender mirror(s) allows you to easily see the blind spots. The driving position is high enough that even if you had windows, they would not provide good “situational awareness” so your driving must adapt to that – just like in a motorhome. You use the mirrors, and you use the side and backup cameras. There is a monitor for viewing those right next to the driver’s seat.

The HDT gives you a much better view down the road since your seating position is up higher. It is far more comfortable than a pickup pulling an equivalent size trailer since it has all air ride; air ride suspension, hitch, cab and air ride seats. There is no “chucking” with the truck either since it is heavy enough to resist that. And, of course, the engine brake means that you never have to worry about going down hills. With the in-built engine braking, you can go down any mountain without ever touching the service brakes.

How Does the Transmission Work?

Our 1999 Volvo 610 had an “Autoshift” transmission. The autoshift transmission requires that you clutch only on starting or stopping. After that, the computer performs all shifting, both up and down – there is no “clutching” required for gear changes. There is a manual mode where you may use push buttons on the transmission stalk to perform shifts – again, with no use of the clutch. The truck will not allow you to perform a shift where you can over-rev or lug the engine. This means the engine is always protected from the driver. One advantage to having a clutch for starting is that when you are hooking to the trailer you can “slip” the clutch, just like on a car, and control your speed better. Earlier truck transmissions without a clutch pedal often have issues with this low-speed backing – especially Freedomline and Ultrashift transmissions.

The newer-generation transmissions that are fully automated properly handle low speed creeping. The Volvo I-Shift that is available in later model Volvo’s (2008 and newer); the Ultrashift Plus also performs quite well, as do the other newer transmissions. 

What Kind of License Do I Need?

I get the license question fairly often. Depending on your state you may need an upgraded license or you may be able to drive on a “car” license. You will have to investigate that issue, based on your domicile. But if you need an upgraded license for an HDT, you will almost certainly need an upgraded license for the “super pickup” class vehicle as well – like the F450/550 and the Dodge 5500. Most states that require an upgraded license do so at a weight limit. I’ll use Texas as an example. In Texas if the combination of the truck GVWR (note that is the rating, not the actual weight) plus the trailer GVWR is over 26,000 lbs you need an upgraded license – in the case of a truck/trailer you need a Class A Exempt (“exempt”, meaning exempt from CDL regulations). An F450 has a GVWR of between 13,050-14,000 lbs, depending on year and equipment. That leaves you around 13,000 lbs for the trailer before you get into Class A Exempt licensing requirements.  Each state will vary somewhat, but more and more states are implementing weight-based licensing requirements. If interested in hearing more about this contact me.

What About Comfort?

People ask about comfort because their current pickups hauling big trailers are so uncomfortable. That is because they are being pushed to their limits and are not designed for comfortable hauling of large loads, even though they may be rated to safely handle the load.

A semi-truck is designed for an 80,000lb (combined) load to be pulled continuously across the country. The cabs are designed for driver comfort – since drivers essentially live in the truck 24/7 while on the road. The truck has creature comforts just like a car does – good climate control, sophisticated cruise control, and an excellent driving position with full adjustment of the steering wheel. It also has a seat that is more like a chair; positioning is more chair-like as far as your legs go, instead of “laying you out” with your legs extended like many cars do. It has an air ride cab, air ride seats, air ride suspension, and an air ride hitch so that trailer movement does not translate to truck movement.

How Does One Choose a “Good” Semi-truck?

Choosing a semi-truck is a little different than choosing a car. But in some ways it is the same….let me explain. The difference is that you generally focus more on miles than on the year. And the number of miles on a semi-truck may seem daunting to most car buyers. That goes back to how semi-trucks are expected to perform. Remember, these trucks are designed to be driven 24/7. If the truck is not moving it is not “working”, and thus is not making money for the company or the driver (most drivers are paid by the mile). A semi-truck that is “team driven” can easily rack up 10,000+ miles a month. The truck and engines are designed for high miles, unlike a car that may only average 20,000 miles a year. In general, the engines in these trucks are designed to go 1,000,000 miles before overhaul. Yes, that is one million.

Maintenance is the key element in finding a good truck. The truck needs to be properly maintained by the driver/company. Buying a truck with a known “provenance” or “pedigree” goes a long way to ensuring that you are getting a good truck. Anything can happen of course, but we maintain our trucks to the highest standards. We generally replace components far before needed. We do not want to break down on the side of the road or be stuck someplace. Since we live “on the road” that is not an option for us. We owned the 1999 Volvo 610 shown above for ten years and it was very reliable. We never broke down in it.

Where Do I Get It Fixed?

Most people never notice all the HDT (heavy duty truck) service facilities. There are places to service/repair these trucks in every town in the country. There are lots of HDT “working” trucks traveling the highways continuously, and they have to get fixed wherever they are. So it is easy to find service for the truck – far easier than for a pickup truck. And, in general, the shop rate for HDTs is lower than for pickup trucks.

What Does It Cost to Rebuild The Engine?

Some people have heard horror stories about HDT’s needing to have the engine rebuilt. While this is VERY rare in RV use, it does happen, and no one can guarantee that it will not happen to a particular truck. But don’t forget, these trucks mostly have engines designed to go one million miles without rebuilding – and many go far beyond that.

Dealing with a “blown” engine takes, basically, three forms depending on the damage.

Typically you can do an “in-frame” rebuild, where the engine remains in the truck and is rebuilt in place. The second choice it to pull the engine from the truck and rebuild it. And lastly, you can get a re-manufactured engine that has been rebuilt by the manufacturer and comes in a crate – called a “crate engine”.

On a Cummins ISM like in our Volvo 610 an “in-frame” rebuild runs around $11K-13K, depending on what is done. Cummins Rocky Mountain was advertising an ISM in-frame rebuild for $10,800 in June 2013. It would not be much more today. It is typical to replace functioning auxiliary components during the rebuild process, simply because you are “in there”, which will add to the price. At the end of the rebuild you typically have an engine with a 2 year/200,000 mile warranty.  From an RV-use perspective, it is a “lifetime” engine.

Our Volvo 780 had a D16 Volvo engine in it. This is a much larger engine than the ISM, and would cost in the $20,000 range to rebuild.

RVH Lifestyles sells two or four-year warranties that cover all the major engine parts, in addition to the transmission, pollution control systems, differential, turbo, etc.  Any truck purchased from RVH will come with at least a two-year warranty, but you can place a warranty on your own truck.

The Bottom Line

An HDT is easy for almost anyone to drive. I have taught many women who have never driven a large vehicle to drive at the HDT Rallies. People adapt very quickly. And the HDT gives you the flexibility to do many things not possible with a pickup: never any concerns about weight again; plenty of power for the mountains; exceptional braking power; use as a motorhome for short trips;  carrying a car, motorcycle or ATV; lots of storage, etc.

Below is a video with further information about tow vehicles.

Getting your RV Hauler Registered in Texas

By Jack Mayer

Texas is one of the states that allows HDT’s to be converted to motor homes, with a resulting motor home (MH) title. The benefits of this are:
– generally lowers your insurance costs
– makes for a compelling case for bypassing scales in most states
– exempts you from the 20,000 lb bridge axle weight (it is 23,000 for motorhomes)
– exempts you from an air brake endorsement in Texas
So for most people it is an attractive option.

If you are already domiciled in Texas it is pretty simple to do the registration either in person or by mail. To file by mail you have to be “out of state”, although no proof of that is required.

I’ve done a number of these registrations by mail in Polk County (home of the Escapees RV Club). This info is from my experience in that county. Polk County is a non-pollution test county. In pollution test counties the procedures may vary slightly.

The Polk County Tax Office phone number is 936-327-6801. You will be calling them once you have the forms prepared to get the rest of the fees due – you will not be able to complete the numbers without talking to them. You need all the items below, before calling. Plus, have your VIN number handy. When talking with them, verify that you have everything required. If you have something wrong with your applications they generally will NOT call you or email you, even if you have provided that information. They will send you a written request, which may take some time to reach you.

Also, you have thirty days to get your application in from the date on the Bill of Sale and title. They enforce this to the day – if you are beyond the thirty days you will have to pay the penalty fee. You might as well enclose it with your original paperwork, or you will be doing it later. You can protest it, and some people have been successful in doing so. But you have to go to/phone the state offices to do that. Polk cannot/will not waive the late fee.

You may also get a temporary registration from the Tax Office. You can get transport tags INTO Texas from out of state or for within TX on the DMV website. In most cases these can be done electronically, printed and used.

Items you need:
– If “out of state” you may file for an inspection exemption. If in-state you must get the truck inspected before application.
– You will need a weight ticket.
– If registering by mail, then a copy of your drivers license (and spouses license if both are on the title) and proof of insurance must be submitted with the paperwork.
– Pictures of the items required for conversion to a motorhome. Refrigerator, sleeping facilities, cooking facilities, toilet, shore power, separate heating/cooling. If you have an APU then a picture of that. Not all of these items are required, and it is turning out that it is somewhat random what they actually want. In October 2017 they specifically asked me about shore power, for example.
– Pictures of all four sides of the truck. The full truck must be in the picture.
– New: you MUST have “Private RV Not For Hire” on both sides of the truck and you must supply a picture of that. Individual pictures are required, NOT just the side pictures of the truck. Don’t ask me why.
– A Bill of Sale, listing EVERY person on the Seller’s title, and EVERY person on the requested new (Buyer’s) title. If you leave one name off, you will have to re-do it. Dealer paperwork will suffice for this.
– The Title from the Buyer. EVERY named person on the title must sign the release. If it is a dealer you bought from they will/should do this correctly, but private buyers may not. Make SURE the signatures and printed names match the title. If they do not, you will have a problem.

Forms to fill out:
– VTR-272-B Vin Self Certification
– VTR-249 Abbreviations for Make and Body Style
– VTR-130-U Application For Title
– VTR-130-UIF Instructions for Application For Title
– VTR-61 Rebuilt Vehicle Statement
– VTR-35-A Personalized Plate
– VTR-122 Rights of Survivorship (if needed)
– VTR-144 Travel Trailer Verification (if also doing your trailer)
– Vehicle Safety Inspection Waiver, Self Certification. As far as I know Polk does not have their own form, I used THIS ONE and modified it to eliminate Harris County. If you know of a State form let me know. The online registration system for renewals allows self certification but I know of no paper form.

The latest versions of these forms can be found on the TX DMV Forms website HERE ( I’m not including direct links here, since these forms get updated over time, and you will want the latest version(s).

You can certify the Rebuilt Vehicle yourself – you do not have to have a builder do it. If you are doing this out of state you will be requesting a waiver of the Inspection. Put a note with the Rebuilt form that you are out of state and are requesting waiver of the inspection on the Rebuilt Form.

You do not need a VTR-64, which is the Assembled Vehicle Safety Inspection. Do not include any info on the second page of the VTR-61 form – this should be marked as Not Applicable. Unless you did re-engine or otherwise heavily modify your vehicle (not typical).

Trailers in TX are a strange thing. Technically, the large 5er’s that we use with our HDT’s should be categorized as semi-trailers according to the legal description. That is NOT how it is done. They are done as travel trailers. Yes, travel trailers. Note that on the form a travel trailer has size restrictions. You may fall outside of the width and length. The advice I have received – and others have received – is to simply put down 40’ long and 96” wide, even if you are larger. You can pursue this on your own if you like, but that is what people have been doing for years with larger trailers that fall outside the regulations as currently written.

The information above was accurate when written. Make SURE you verify current rules and regulations. The above should be viewed as guidance, only.

Truck Conversion Overview

By Jack Mayer

This article assumes starting with a tandem truck just off commercial service. It describes the items that we commonly do to “convert” the truck to RV use. While these are things that we commonly do, you can do more or less during a conversion project. The components specified are our recommendations, but other equivalent components are available in most cases. We specify these because we feel they are “best in class”, and are what we use personally. 
While you “can” hook up an RV to a commercial truck, the lighting will not work, there will be no brakes,  and the commercial hitch will beat the RV up pretty well, in most cases. Some people do run commercial hitches with RVs but we recommend removing the commercial hitch if it is not required for your mission profile – and replacing it with an RV suspension hitch behind the axles.
RVH Lifestyles provides a wide variety of services and products for the recreational HDT community. This article focusses on conversion topics.

The following is our view of the minimum required to convert a commercial truck for RV use:
– Remove commercial hitch
– Add fenders to the wheels to protect the front of the RV. Note this is not necessary if putting on a body.
– Add Direclink brake controller with an appropriate HD module.
– Add TST TPMS (tire monitor) system to the truck, with 6-10 sensors (depending on if you stay tandem). We use the Color display mounted overhead in the storage area. Extra sensors can be supplied for the trailer.
– Add the RVH Electrical center (includes Jackalope). This provides for RV light conversion and the future use of electrical accessories. It includes a DC load center with fuses, and terminal strips to pick up lighting signals. It comes with the seven-way trailer wire to reach the back of your truck, and a 7-way connector to plug your trailer into. It also comes with enough #6 wire to connect directly to your battery bank to supply the 12-volt load center, and a circuit breaker for that line. So basically everything you need to properly hook up your trailer and to support future expansion needs.
– Add an ET hitch rated for (typically) 5K-8K pin weight. On a tandem truck, this requires some frame extension – about 2’. The ET sold by RVH Lifestyles has the new upward dampeners in it, the new longer release arm, and the specialized ET head in place of a Binkley head. The ET head is serviceable and heavy-duty – the Binkley head is not serviceable. The ET is upgradeable to (up to) a 10,000 pin weight version if required in the future. Note that in most cases we prefer the ET hitch to a Comfort Ride. We are Comfort Ride dealers as well as dealers for ET, so can supply either, and discuss with you the benefits of both hitches. In most cases, an ET is priced about the same as a Comfort Ride, since it comes with a mounting plate and angle for mounting, while that needs to be added to the Comfort Ride.
– At least one backup camera at the hitch and a 9” monitor at the dash. The monitor is surface mounted. A DVR system that records 6, 9 or 17 channels or a quad-view camera system is an option that can replace the simple display. Also, evaluate providing a video hookup at the rear of the bed to support three trailer cameras.
– Wire a 7-way RV blade socket at the rear of the truck for towing an RV trailer. This requires the RVH Electrical Center or the equivalent function. In the picture below you see (on the left) a typical 7-way connector for RV lighting, and below that, a smaller connector for video feeds from the trailer to the Quad monitor or to the DVR system. Three cameras on the trailer can be passed to the truck video system (without sound). Note, the gladhands on the right side are options for air systems, or for easily filling tires.
If you have hydraulic disc brakes on your trailer we can upgrade your trailer brake system to BluDot so that it operates off your truck air system – just like a “regular” semi-trailer. This gives you “best in class” braking for your RV. If you do this a brake controller for electric brakes is not required in the truck, although you might want it to be compatible with a “standard” RV.
– The other thing we do to almost every truck we convert is to change the vertical exhaust stack to a weed burner (horizontal) exhaust. This frees up space for the drom box and allows for additional storage. It also keeps exhaust off the trailer – although with full pollution trucks (trucks with DPF and DEF) exhaust soot is not really a factor). The cost of the weed burner conversion is typically under $1000 and allows for use of a drom box between the cab fairings.


We generally convert most trucks to single axle from tandem axles. Singling is mostly a personal preference, however, it adds significant cargo space to the bed design, and simplifies ongoing maintenance quite a bit. It also improves maneuvering if done correctly.  If carrying any deck cargo heavier than a smart car, we recommend staying as a tandem, since you would likely be pushing the carrying capacity of the rear (single) axle – which is usually rated in the 19,500 lb area. While you could find a 23K-rated rear axle for a singled truck, it is rare to do an axle swap. However, we can do that work if desired.
Singling involves removing the forward-most rear axle and relocating the rearward one. There are three positions commonly used to relocate the axle. “Short” which is to place the axle in the forward position where the “removed” axle was. “Long” which is to leave the rearward axle in its original location. And “Mid”, which locates the axle someplace in between the two original locations.  

Extending the frame. In this case, we are adding enough length that we “sister” in support structure inside the frame extension. This adds incredible strength to the extension.
Generally, we recommend the “mid” (middle) solution, since it balances the looks of most trucks better, and allows for a deck that can carry cargo without excessive cantilever of the hitch. This does require drilling new hanger holes, which the other options do not. So it adds to the work and cost (somewhat). But in the end, you get a better solution.
The exception is if the mission profile requires a truck that is a “daily driver”  not designed to carry a car or other significant deck cargo requiring a large(r) deck. In that case, singling short is probably a better solution, since it significantly shortens the wheelbase and provides for a shorter overall vehicle and far better maneuvering capability. If you are driving the vehicle every day, this is a significant benefit. A Volvo 730/780/860 singled short can have a wheelbase as short as 205”, and a 630/640 could be as short as 183”. This depends on several factors, including fuel tank size and position. A singled-mid Volvo 730/780/860 is typically a 236” wheelbase. When singling to carry a smart car, we position the axle at 99” BOC (back of cab) – which is the 236” wb of the 730/780/860.
We never recommend singling “long”. There is no advantage, other than ease of implementation, in doing so and there are significant disadvantages. Mainly, overloading the front axle with deck cargo, significant maneuvering issues vs. mid or short, and looks (the truck looks unbalanced). Singling long may also result in a longer-overall truck since most suspension hitches used with HDTs require being set inside the frame rails. Singling long means having to extend the frame rails to locate the hitch; resulting in a longer overall vehicle than if the axle was more forward, to begin with. 
When singling a truck, a new driveshaft must be built for the new length – this is true no matter which position choice is made. A new yoke to attach the driveshaft to the differential is required, and you may have to add/move a carrier assembly to support longer driveshafts. You also relocate airlines, leveling valve, valves/solenoids and support brackets to service the new location. U joints are checked and replaced if required.  During this process, we generally clean the frame up and paint it (as required), service/replace brakes, suspension elements, torque arm bushings, etc. Often airbags are replaced, and brake cans are replaced. We also take the opportunity to fully service the cab suspension. This means replacing the airbags, the shocks, perhaps the cab leveling valve, control arm, bushing, and realigning the cab (most of them lean). The ABS brake system is reprogrammed to operate properly and to interface with the Volvo VEST system properly. See video below for more information.
There is a great deal of discussion about the value of singling in the HDT community. While you do not have to single a truck, it does have some advantages, and of course some disadvantages. The main disadvantage is the initial cost. Singling, along with the corresponding repairs/improvements discussed above typically averages in the $7,000-$12,000 range. But remember, some of that is actually repairs and improvements, not “just” singling.
One of the things you often hear about singled trucks is that they do not ride as well as tandem trucks. While this may be true in a specific set of circumstances – like going over speed bumps, where the rear is always supported by the tandems – we do not find it to be generally true in RV use. Consider the design goals of the original truck – it is designed to carry significant weight on the rear axles – upwards of 35,000 lbs. And it has a suspension designed for that purpose. So even though it has air ride, it is still pretty “stiff” in the rear when tandem. We have driven the same roads with the same model truck that were both tandem and single and frankly don’t find much difference in them when in RV use or bobtail. This would not be applicable to commercial operation with different loading factors.
Additional items like various bed designs, APUs, lighting, trim/chrome, seating revisions, etc are upgrades to “make your truck your own”, and to provide additional comfort and capabilities. But none are “required” to convert to RV use.
If it can be done to an HDT, we can do the work – from mechanical to appearance items, we do most of the things that make the truck an exceptional recreational hauler.