In 1992, New Venture Gear in Syracuse New York built the first NVG4500 transmission for the Chrysler corporation to use in their heavy duty truck applications. The Dodge NVG500 was a much needed improvement from its predecessor the G360. Soon after its creation the letter G was dropped from the name to give us the more commonly known NV4500 transmission.
The NV4500 transmission is available for both 2WD and 4WD vehicles in either gasoline or diesel applications; the 2WD version has a longer housing than the relatively short 4WD tranny case, which is just over 12 inches long. The NV4500 was used for Chrysler and General Motors vehicles for production years 1992 through 2007 in the Muncie, Indiana facility. The NV4500 was used in SUV and truck vehicles made by Dodge, Jeep, Ford, Toyota and Chevy, including both ¾-ton and 1-ton vehicles and the Ram 2500 and 3500 trucks; it can be used for both short block and long block V8's. It is also used in V10's and in Cummins diesel vehicles that have a gross vehicle weight rating up to 14,500 pounds.
Originally assigned part number 12346190, the New Venture Gear NV4500 is a 5-speed, top-loading transmission that was originally hailed as the ultimate 4WD tranny and its popularity skyrocketed. This led to dramatically increased prices for this tranny and prices remain high for it. Although this tranny has a fifth gear overdrive, its 6.07 gear span and 6.34:1 low gear ratio make it less attractive for some applications than heavier duty trannies. Newer models of the NV4500 have a higher low-gear ratio; all have either a .74:1 or a .73:1 overdrive ratio
Originally, only forward gears were synchronized, but reverse gears were also synchronized in 1996 and all gears utilize synchronizer rings that are made of a carbon-fiber composite. Some companies have more recently upgraded the syncro rings to solid brass, which seems to add longevity and make them much less finicky on fluids. Special synthetic GL4 lubricant is required for the carbon style synchronizer rings. New Venture Gear recommended gear oil is:
- 75W-90 Castrol Syntorque Synthetic.
- Mopar PN 4974459 75W85 manual tranny lubricant.
- GM Synthetic Manual Transmission Fluid PN 12346190.
One of the unique and attractive characteristics of the NV4500 is the 1st to 2nd, fly-weighted synchronized gear assembly. This is a safety feature that prohibits downshifting at high rpms. One major problem with this tranny is 5th gear failure, which causes the tranny to either pop out of fifth gear or not get into it. This has been a consistent issue since the NV4500 hit the market and is caused by the fifth-gear nut backing off the main shaft. Installation of a main shaft upgrade kit can help correct the 5th gear problem.
The N4500 has a cast iron case with tremendous gear sets, an aluminum top cover, helical gears, dual PTO ports, fifth gear overdrive and a granny gear for towing. Adapter kits are available that enable installation in almost any vehicle, including those with a short wheel base; this tranny weighs about 200 compact pounds.