2004.5-2007 Dodge 5.9L Cummins Transmissions & Parts

Transmissions in the 2004.5-2007 Ram 5.9L Cummins

These trucks were badged Dodge Ram 2500 and 3500, sold in ST, SLT and Laramie trim, and they left the factory with one of three transmissions. Most got the Chrysler 48RE four-speed automatic, a descendant of the old A727 three-speed with an overdrive unit bolted on the back. Its ratios are 2.45, 1.45, 1.00 and 0.69, with a 2.21 reverse, and it runs ATF+4. Chrysler did strengthen it over the 47RE: a 10-lobe pump with tighter clearances, a larger direct drum with five frictions, a 93-tooth forward clutch spline and six-pinion steel planets. From mid-2004 an electric throttle valve actuator, the TTVA, replaced the old mechanical TV cable. Manual buyers got the NV5600 six-speed through 2005 and the Mercedes G56 six-speed from mid-2005, and the G56 is the only manual for 2006 and 2007. The G56 came with a dual-mass flywheel. In front of all of it, the engine makes 325 hp, with 600 lb-ft in 2004.5 and 610 lb-ft from 2005 through 2007.

What fails and why

The 48RE gives out first. Its 560-570 lb-ft input rating is below what the engine makes stock, and shops that build these units report failures between 100,000 and 150,000 miles even on trucks at factory power. Watch for slipping, lost torque converter lock-up, no overdrive, burnt fluid, and shifts that are not right. Add power and the ceiling arrives sooner: input shafts have snapped at as little as about 500 rear-wheel horsepower, and you find out with a sudden loss of drive.

Manual trucks have their own pattern. The G56 dual-mass flywheel holds up poorly under heavy hauling or above-stock power, and it shows as clutch engagement trouble, rattle and chatter. The G56 has also been reported to suffer input-shaft bearing failures tied to splash lubrication and heat, and bellhousing cracks under excessive torque. The earlier NV5600 drew complaints while towing: hard shifts, synchro wear and clutch slip.

Stock replacement vs. upgrade

On a stock automatic, fluid and filter service is the cheapest insurance you can buy. The owner's-manual schedule lists fluid and a band adjustment at 100,000 miles; shops that build 48REs say fluid, filter and band every 30,000 miles, and that is the schedule we would keep on a truck that works. When the unit is worn out, a built 48RE package sold by horsepower and use level, with an upgraded converter and valve body, is a better buy than a stock rebuild, because the stock rating is already short of the engine. If you plan to add power, buy the built transmission first and stick to CARB EO-numbered parts, verified per product and model year. On a G56, many owners switch to a single-mass flywheel clutch kit for lower cost and better reliability and accept a little more gear noise.

What we carry

• Complete transmissions: BD Diesel 48RE transmission and converter packages and an ATS Diesel Performance 48RE package, plus the ATS G56 performance manual.
• 48RE internals and controls: BD Build-It kits, billet shafts, valve bodies and a valve body electronics upgrade kit, torque converters, and an ATS 47RE/48RE governor pressure switch (transducer).
• Cooling: Mishimoto replacement and universal coolers plus radiator bundles, a Fleece Performance Engineering cooler and line kit, and a CSF OEM-style cooler.
• Pans, gaskets and filters: deep pans from PPE, XDP and Mag-Hytec, a Mahle pan gasket, and a Mag-Hytec pan filter.
• Flex plates and mounts: XDP flex plates and bolts, a DNR Customs install kit, and Anchor transmission mounts.
• Fluid: automatic and G56 fluid from Hot Shot's Secret and Lucas Oil.

Fitment notes

Know which transmission you have before you order. A 2005 truck can have either the NV5600 or the G56, so check the shift pattern or the transmission label. 2007 is a split year: trucks built after January 1, 2007 got the 6.7L Cummins and the 68RFE six-speed automatic, so match a 2007 by engine, not model year. A 2004.5 truck is a 2004 model year, and some packages here are titled 2005-2007, so confirm those by VIN. Some packages are drivetrain-specific, so know whether you have 2WD or 4WD. The Power Wagon of this era is a Hemi truck, not a Cummins. For everything else on this engine, start at our Cummins page.

Frequently asked questions

Is the 48RE strong enough for a stock 5.9L Cummins?

Not on paper. It is rated for 560-570 lb-ft of input torque, and the 2004.5-2007 engine makes 600-610 lb-ft. Shops that build these units report failures between 100,000 and 150,000 miles even at factory power. Regular fluid and filter service buys time; a built unit is the long-term answer.

What fluid does each transmission take?

The 48RE takes ATF+4, about 4 quarts at a pan service and 14.5-16.5 quarts dry. Ram specifies ATF+4 for the G56 while Mercedes lists gear oils, so find out what is already in yours before you top off. The NV5600 calls for Mopar fluid 4874464, 4.75 quarts.

Is my 2005 manual an NV5600 or a G56?

It could be either. The G56 began replacing the NV5600 partway through the 2005 model year. Check the shift pattern or the transmission label before you order fluid, clutch or shifter parts.

Are there recalls that touch these transmissions?

Two are worth checking. 2005 diesel automatics got an out-of-park alarm through a software update under recall 05V462000. Manual trucks have a clutch ignition interlock switch recall, 14V795000, and a no-start on a manual may be that switch. Run your VIN through NHTSA's recall lookup to see what applies to your truck.

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.