Stretching It

Published in the October 2008 Issue October 2008 Build, Cummins

Long truck

For the Dodge and/or Cummins fans out there, the arrival of the Mega Cab was a glorious thing. News of the "mega truck" came as a rumor. Then when the truck was first seen, for many it became the ultimate truck. To have such a spacious cab with enough room in the back seat to deserve a mini-bar was a dream come true.

Then, when we looked for the long bed version and found there was none nor any plans for one, our hopes and dreams of the perfect truck fell and shattered on the floor. After all, if you've ever had much to haul or tow, you know that an 8-foot bed is a must, especially if you tow fifth-wheel or gooseneck trailers. Yes, you can avoid crunching your cab as you back your fifth-wheel if you use a "slider" hitch that extends toward the rear of the truck when you back up, but the wheelbase of a long bed adds stability, improved handling and safety when towing or hauling a load that you quickly learn to appreciate on those long road trips. It looked like you'd have to settle for the Quad Cab long bed.

Until now.

It's time to sell the Quad Cab, score an amazing deal on a Mega Cab and turn it into your ultimate hauler.

WHERE TO GO

We took our new (factory overstock) 2007 5.9L Mega Cab 3500 DRW to Precision Bodyline in North Salt Lake, UT, to have it stretched to proper specifications. We chose Precision to do the job because its solution to the conversion is engineered for maximum strength and the company has extensive experience (62 trucks converted to date).

People ship their trucks to these guys from all over the country. Precision knows what works and what doesn't. We also liked the fact that Precision is a collision repair shop, so they have all the equipment and tools necessary to properly align frames of damaged vehicles, making us feel better about simply extending our new, straight frame.

For those of you who have seen long bed Mega Cab trucks on the road across the country with sagging frames under a heavy load, fear not. A few different shops have attempted the conversion, but Precision has mastered it. They've eliminated the possibility for sag by engineering their frame splice to be placed in the center of the bed, above the axle, cradled between the spring mounts. This way, there is less stress placed directly on the splice. Most trucks experience sagging when the frame is spliced under or directly behind the cab, where the splice is forced to support the weight and load of the truck in two equal halves.

Another benefit to splicing the frame under the bed is that it gives a gooseneck or fifth-wheel hitch a more secure attachment. The reinforced splice is thicker and more rigid than the factory frame where these hitches attach. Finally, the last benefit to consider is the fact that they don't have to relocate cab mounts, fuel tank mounts, fuel lines and cross members, keeping as much of the factory setup in place as possible.

HOW IT'S DONE

The first step in the conversion is to remove the bed. The short bed is traded for credit toward the factory long bed that will be used on the truck.

Next, they remove the driveline, shocks, and spare tire. The exhaust gets cut and brake lines (hydraulic and parking) and wiring are disconnected. The frame is supported on jack stands and the springs and rear axle are removed together.

The frame is then cut with a plasma torch in the same tabbed shape that the factory connections are made to allow for additional surface area when the metal is welded to the attaching section. To extend the frame Precision uses a double-walled splice section. The inner section of the splice fits snugly inside the existing frame. It's twice as thick as the wall thickness of the frame. The truck's frame is extended 20 inches, but the inner sleeve that is inserted is 35 inches. They actually have to pound the inner sleeve into the frame 7.5 inches on each end before it's welded into place by their ICAR certified welders.

Next, the outer sleeve, which is the same thickness as the factory frame, is welded into place over the inner sleeve. This reinforces the inner sleeve and makes the outside frame dimensions the same as factory, so any accessories or hitches can be mounted as they were intended.

After the frame is lengthened, the factory contact overload brackets are removed and reattached 20 inches farther back on the frame. The front leaf spring hanger and passenger-side shock mount are then removed and moved back 20 inches as well. Our rear spring hanger stays attached to the rear factory frame section.

All bare metal is then primed and painted with a rust-proof, two-stage epoxy paint.

Next, the rear axle, springs, shocks, spare tire and exhaust (extended) are reattached. Precision then adds its custom electrical extension loom, which gets hard-wired into the factory loom, then sealed with water-tight heat shrink tubing. Hydraulic brake lines are extended using hard lines, and the parking brake is extended using a factory-type connection.

The rear driveline must also be extended. For this, the truck is taken to Six States in Salt Lake City. The 2006-07 Mega Cab comes with two-piece drivelines from the factory that must be lengthened and balanced. Late `07 and all `08 trucks came with one-piece drivelines that are made into two-piece drivelines with the addition of a carrier bearing. They must be balanced and installed at correct angles.

WHILE WE'RE AT IT .

We also had Precision install a PopUp Industries PopUp 2 gooseneck hitch. It has a 30,000-pound trailer weight rating and a 7,500-pound vertical tongue weight rating. But the best part about this hitch is the hitch ball is hidden and leaves our bed flat when not in use. However, when it's time to use the hitch, you just pull a rod in the driver side wheel well and the ball pops up and locks into place. To retract the ball, you push the rod back in and the ball drops back into its hiding place below the bed. The installation of the hitch was smooth and the construction and connection to the truck are heavy-duty. After seeing and installing this hitch, Precision actually became a PopUp dealer.

Another must-have in our ultimate truck is load support. There's nothing worse than a truck that sags in the rear under the weight of a trailer. It looks terrible and drives even worse. We decided to add a set of Air Lift LoadLifter 5000 air bags. They have a 5,000-pound leveling capacity and are adjustable from 5 to 100 psi so that you can adjust the height and stiffness of the vehicle suspension under heavy loads. These allow us to stabilize the truck and keep more weight on the front axle to keep firm steering contact with the road. The air bags are adjustable manually using two tire valve stem connections that you mount in a location of your choice or you can add a compressor for in-cab adjustability.

We used Air Lift's new WirelessAir compressor. We mounted the compressor to the top of the relay box under the hood and supplied power from the truck's battery. Air lines were run along the frame back to the air bags. A control box, mounted near the compressor, monitors air pressure in the bags and controls the compressor. The control box and compressor are controlled using a remote that mounts to the truck sun visor. You can adjust the air pressure in the bags from inside the truck or outside as you visually level the load. The remote controls pressure in both air bags simultaneously or individually so you have complete control over leveling the load torsionally and laterally. This system has worked great.

In order to stop our loads, we added an Odyssey II trailer brake controller by Valley. We chose this controller because it's smart. It responds quickly and smoothly regardless of your speed. If you've towed with more primitive controllers, you know how it is to be constantly adjusting the gain on the controller, depending on your speed and weight of the load. This controller has four memory presets so you can set the required amount of power for different trailers you tow and their weights. Simply assign one for empty weight and another for the loaded weight of your utility trailer. Set the third for your fifth wheel. This controller is also modular so it can be used in multiple vehicles. Just slip it out of its mounting bracket and unplug the connector on the back and take it to use in another vehicle. We also like its pressure-sensitive manual trailer brake switch for more precise manual control of the brakes. Lesser controllers are simply on or off.

ROLL ON

Finally, the Mega Cab was outfitted with a two-inch leveling kit from Hell Bent Steel and 22.5x8.25 Alcoa wheels and BF Goodrich ST230 255/70R22.5 commercial tires. These are commercial steer tires that are the size we wanted to fit the truck. However, steer tires don't provide enough traction for use in all four seasons on our ultimate truck, so the tires were re-tread with Michelin XDE M/S tread to give us an all-terrain/mud-terrain tread. Eight-lug-to-10-lug adapters were used to mount the commercial wheels. The 16-ply commercial tires have a much stiffer ride than the stock E-rated tires, but offer much more stability under heavy loads, high mileage (100,000-200,000 miles) and better highway fuel economy due to the increased tire diameter (just over 36 inches).

PROVING GROUNDS

We've tested the setup by hauling a 17,000-pound trailer with 2,500 pounds of the load in the bed as well as other combinations. So far, we've logged more than 11,000 hauling miles following the conversion without any problems or defects. The truck pulls very well with its 15-foot wheelbase, air bag support and dual rear wheels. It's smooth and stable. When pulling our gooseneck at night, it's easy to forget that we're towing a trailer. Out of sight, out of mind. There is some noticeable steering wobble with the large wheels and tires. Late model Dodge trucks are known to have this characteristic. We will install an aftermarket steering brace to help correct this issue. Another item on our to-do list is new shocks. The increased weight of the Alcoa wheels and commercial tires adds more unsprung weight than the factory shocks were designed to dampen. Some wheel hop is noticed on the highway. A set of heavier-duty shocks should remedy this problem.

And so begins our Long Bed Mega Cab project truck. Now that we've got our desired platform to start working with, we'll proceed to build our Dodge hauler. Stay tuned for this build in issues to come.

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