2004.5-2007 Dodge 5.9L Cummins Towing Parts

Towing with the 2004.5-2007 Ram 5.9L Cummins

The 2004.5 update made this engine the first pickup diesel rated at 600 lb-ft, and from 2005 it is rated at 610 lb-ft at 1,600 rpm. It sits in front of either the 48RE four-speed automatic or a six-speed manual, first the NV5600 and then the G56 from mid-2005. The rear axle to expect is the AAM 11.5-inch full-floater; count the cover bolts to confirm, since the 11.5 has 14. What the truck does not have is any towing prep in the bed. This generation has no factory puck system, so gooseneck balls and fifth-wheel rails install on brackets under the bed. At the back, aftermarket receivers come in Class III, IV and V, and the Class V hitches use a 2-inch or 2.5-inch opening. Browse hardware for every truck on our hitches page, and the rest of the engine lineup on the Cummins page.

Where towing setups run into trouble

The most common towing complaint on these trucks is rear leaf sag under fifth-wheel or gooseneck pin weight. The rear sits low, the headlights aim high and the trailer pushes the truck. Air helper springs with a compressor are the usual answer. Brakes come next: towing without working trailer brakes overheats the truck's pads and starts rotor thickness variation, which you feel as pulsation after a heavy tow.

Then there is the transmission. The 48RE automatic is rated for 560-570 lb-ft of input torque, below the engine's 610 lb-ft, and heavy towing on top of added power is what kills it. If you add power, use CARB EO-numbered products only, verify them per product and model year, and keep it conservative, or build the transmission first. One more item for owners of 2005 automatics: recall 05V462000 added an out-of-park alarm by software because a driver could leave the 48RE in Reverse without engaging Park. Confirm it was done on your truck.

Factory hitch vs. upgrade

If your truck has a factory hitch and you tow bumper-pull trailers well inside the ratings, a good adjustable ball mount may be all you need. Receivers come in versions for trucks with and without the factory hitch, and most install with no frame drilling. Step up to a Class V 2.5-inch receiver if the truck has no factory hitch or you need a higher hitch rating. Aftermarket Class V receivers for these trucks are rated up to 20,000 lb gross trailer weight and 2,700 lb tongue weight, but that is the hitch's number, and your truck's own rating governs. Past bumper-pull, the in-bed options are an under-bed gooseneck or a fifth-wheel rail and bracket kit, and short-bed Quad Cab and Mega Cab trucks usually want a slider. If you tow heavy, 75W-140 synthetic is the spec for the AAM 11.5 rear axle.

What we carry

From B&W Trailer Hitches: Tow & Stow adjustable ball mounts with 2-inch, 2.5-inch and 3-inch shanks in standard, pintle and MultiPro/MultiFlex styles, with drops from 2.5 to 9 inches; heavy-duty and triple-tow ball mounts; hitch balls; reducer sleeves; the WDHK4500 weight distribution hitch; and Turnoverball gooseneck hitches. Big Hitch Products adds 2-inch and 2.5-inch receivers for stock-bumper and roll-pan trucks, including hidden receivers that sit behind a roll pan and a bed-below-roll-pan version, plus adjustable pulling hitches and a 7 and 4 pole trailer connector socket with mounting bracket. Air Lift covers the air side with WirelessONE compressor systems and tank kits, an app-controlled WirelessAIR system, a heavy-duty dual load controller and a LoadLifter 5000 Ultimate Plus stainless steel upgrade. Lucas Oil 10030 5th Wheel and Slider Lube rounds it out.

Fitment notes

This collection covers the 2004.5-2007 Dodge Ram 2500 and 3500 with the 5.9L Cummins: Regular Cab, Quad Cab and Mega Cab (2006 and later), short and 8-foot beds, and the 3500 in single or dual rear wheel. Cab-and-chassis trucks have a different frame and bed and are excluded from pickup gooseneck fitments. Look under the bumper before you order a receiver, since the with-hitch and without-hitch versions are different parts, and expect to lower the spare tire on some installs. The Power Wagon of this era is a Hemi gas truck, not a Cummins, so it is not covered here. On a 2007, confirm the engine: the 5.9L was retired partway through the model year, and trucks built after January 1, 2007 got the 6.7L.

Frequently asked questions

Does a 2004.5-2007 Ram have a factory gooseneck or fifth-wheel prep?

No. This generation has no factory puck system in the bed. Gooseneck balls and fifth-wheel rails install on under-bed brackets made for the truck, and B&W's Turnoverball gooseneck hitches are built for that kind of install.

Should I run a 2-inch or 2.5-inch receiver?

Class V receivers for these trucks come in both. The 2.5-inch is the pick if your truck has no factory hitch or you need a higher hitch rating. Remember that the hitch rating is not the truck's rating; your truck's own rating governs.

Why does my truck squat when I hook up the fifth wheel?

Pin weight bears down on the rear leaf springs, so the rear sits low, the headlights aim high and the trailer can push the truck. Air helper springs with a compressor are the standard fix for that sag, and the Air Lift compressor and control systems here handle the air side.

What gear oil should the rear axle run if I tow heavy?

Heavy towing calls for 75W-140 synthetic in the AAM 11.5 rear axle. Count the cover bolts first to confirm what you have: the 11.5 uses a 14-bolt cover.

My brakes pulse after a long tow. What happened?

Towing without working trailer brakes overheats the truck's pads and starts rotor thickness variation, which shows up as pulsation. Before the next trip, make sure the trailer's brakes work and the truck-side connection is sound.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.