2003-2004 Dodge 5.9L Cummins Torque Converters

Torque converters on the 2003-2004 Ram 5.9L Cummins

The converter couples the Cummins to the automatic and, once it locks up, ties the engine straight to the input shaft. On the 48RE, lockup engages in tow/haul mode and keeps the transmission out of overdrive, and the 48RE improved 2nd- and 3rd-gear lockup over the 47RE. Chrysler rated the 48RE at 560-570 lb-ft of input torque, which is why the engine was detuned behind the automatic.

What fails and why

Transmission builders point to two problems with the factory unit: limited clutch area and a low-quality cast apply piston that flexes when the converter locks. Owners see it as slipping lockup, shudder and high transmission temperatures while towing. Towing in overdrive adds heat, and once fluid passes 260F the 48RE forces protective downshifts. Where the converter bolts to the engine, an overly rigid flexplate can balloon or break, so a reinforced steel or SFI billet plate belongs on the list.

Stock replacement vs. upgrade

A stock-style converter makes sense on a standard-output truck that works light. Many buyers go the other way: one major builder reports about 80% of the replacement converters it sells are lower stall than factory, and a lower-stall billet triple-disc converter with an upgraded stator and apply piston is the usual first 48RE upgrade. If you plan to go past roughly 500 hp with lockup, the stock input shaft becomes the next weak link; Diesel Hub reports they snap with as little as 500 rwhp.

What we carry

BD Diesel offers the Triple Torqueforce Low Stall converter and the Proforce converter, plus the HI5 rebuild kit if you would rather refresh the converter you have. ATS Diesel Performance offers its Five Star Performance converter in a factory-style version, plus Five Star converters built for 5.9L Cummins trucks that have been converted to a Ford 4R100 or 5R110 automatic. Those conversion converters do not fit a 47RE or 48RE.

Fitment notes

Early-2003 standard-output trucks (VIN 8th digit 6) may have the 47RE; the 48RE has a 5-prong neutral safety switch and the 47RE a 3-prong. A 48RE converter fits a 47RE, but a 47RE converter does not fit a 48RE. Most listings here read 1994-2007, so confirm the stall speed and transmission match your truck, and verify by VIN before you order.

Frequently asked questions

Should I pick a low-stall converter for towing?

For most towing trucks, yes. One major builder reports that about 80% of the replacement converters it sells for these transmissions are lower stall than factory, and a lower-stall billet triple-disc unit is the usual first upgrade. In this collection, look at the BD Triple Torqueforce Low Stall.

Can I rebuild my factory converter instead of replacing it?

Yes. The BD HI5 rebuild kit is listed for 1994-2007 Cummins converters. Whether a rebuild or a new converter makes more sense depends on how hard the truck works; call the shop and we will walk through it.

Will a 47RE converter fit my 48RE?

No. Converters interchange one way only: a 48RE converter fits a 47RE, not the reverse. If your 2003 is a standard-output truck, check the VIN 8th digit and the neutral safety switch before ordering.

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.