NV5600 Transmission

Specifications

The NV5600 transmission is a heavy-duty 6-speed manual transmission manufactured by New Venture Gear and was factory-installed in 1999-2005 Dodge Ram 2500/3500 trucks especially those with the 5.9 L Cummins diesel engine. It features a cast-iron case with an aluminum bellhousing, a 1-3/8 input shaft, and all forward gears plus reverse are fully synchronized for smoother shifting. The gear ratios are 5.63:1 (1st), 3.38:1 (2nd), 2.04:1 (3rd), 1.39:1 (4th), 1.00:1 (5th), 0.73:1 (6th) and 5.63:1 in reverse, with sixth gear acting as an overdrive.

The unit is rated to handle up to about 550 lb-ft of input torque (with some heavy-duty variants up to 650 lb-ft), weighs roughly 360 lbs, and holds about 9.5 pints of specified manual transmission fluid. It’s known for its robust construction and wide ratio spread, making it suitable for towing and hauling applications in diesel trucks.

COMPATABLE MODELS

Dodge Ram 2500 (1998–2005)

In the Dodge Ram 2500, the NV5600 six-speed manual transmission was most commonly paired with the 5.9L Cummins diesel engine, making it a favorite among owners who needed serious towing and hauling capability. Its wide gear ratios allowed for excellent low-end control when starting heavy loads, while the overdrive sixth gear helped keep engine RPMs low during highway driving. The transmission’s cast-iron strength and high torque rating made it well-suited for work-oriented Ram 2500 applications, contributing to its reputation for durability and long service life. 

Dodge Ram 3500 (1998–2005)

The NV5600 was a natural fit for the Dodge Ram 3500, where maximum strength and reliability were critical. Used primarily in heavy-duty diesel configurations, this transmission handled the high torque output of the Cummins engine with confidence, especially in towing, commercial, and chassis-cab applications. Its fully synchronized gears improved drivability despite its heavy-duty nature, while the low first gear and strong reverse ratio made maneuvering heavy trailers and loads easier in demanding work environments.

Dodge Ram 1500 (Limited 2004 models)

A small number of 2004 Dodge Ram 1500 trucks equipped with specific heavy-duty towing packages were fitted with the NV5600, making them relatively rare. In these applications, the transmission provided capabilities well beyond the standard half-ton offerings, giving owners a manual gearbox capable of handling increased loads and torque. While uncommon in the Ram 1500 lineup, the NV5600-equipped models benefited from the same robust construction, smoother acceleration, and overdrive cruising advantages found in the heavier 2500 and 3500 trucks. 

Frequently Asked Questions