48RE Transmission

Specifications

The 48RE transmission is a heavy-duty, electronically controlled 4-speed automatic transmission used in 2003–2007 Dodge Ram 2500 and 3500 trucks equipped with the 5.9L Cummins diesel engine. From the factory, it can handle about 570 lb-ft of torque, making it well suited for towing and hauling. It features gear ratios of 2.45:1 in first, 1.45:1 in second, 1.00:1 in third, and 0.69:1 overdrive, with a 2.20:1 reverse, allowing strong low-end pull and lower engine RPMs at highway speeds. The transmission uses ATF+4 fluid and operates with a cable-driven throttle system in 2003–2006 models, while 2007–2008 versions use an electronic “fly-by-wire” TTVA system.

Internally, the stock clutch setup includes 5 direct clutches, 4 forward clutches, 5 overdrive brake clutches, and 10 overdrive direct clutches, which are adequate for factory power levels. Many aftermarket builds upgrade the valve body to higher line pressure and add components like billet torque converters, billet input and output shafts, and increased clutch counts, allowing a properly built 48RE to reliably handle 450 horsepower to well over 1,000 horsepower depending on the build.

Engine Variants

Dodge Ram 2500 (2003–2009) – 5.9L & 6.7L Cummins Diesel

The 48RE transmission is a heavy-duty 4-speed automatic transmission used behind Cummins diesel engines in Ram 2500 trucks. It features electronic governor pressure control, lock-up torque converter, and strengthened internals compared to the earlier 47RE. Designed for towing and work use, it handles high torque but is known to benefit from upgraded valve bodies and cooling when used under heavy load.

Dodge Ram 3500 (2003–2009) – 5.9L & 6.7L Cummins Diesel

In Ram 3500 applications, the 48RE transmission serves as a workhorse for high-GVWR and towing-focused trucks. It shares the same core design as the 2500 version but is commonly paired with heavier-duty driveline components. The transmission is optimized for torque delivery and durability, making it suitable for commercial and heavy hauling use, though proper maintenance is critical for longevity.

Dodge Ram V10 Gasoline (Selected 2003+ Models)

Some Dodge Ram trucks equipped with the 8.0L V10 gasoline engine used the 48RE due to its ability to handle high torque output. In this application, the transmission offers firm shifts and towing capability but operates at higher RPM ranges than diesel versions. Calibration and torque converter characteristics differ slightly to suit gasoline engine performance.

Frequently Asked Questions