The NV4500 or New Venture Gear 4500 is a heavy-duty, manual shift, five-speed overdrive, longitudinally positioned transmission.

History
New Venture gear was the somewhat unlikely merging of the two manual shift design & manufacturing divisions of General Motors and Chrysler Corp. The Muncie (or Stewart Muncie) division of GM and the New Process division of Chrysler became New Venture and one of the first fruits of this union was the NV4500.

The NV4500 was first released in Chevy / GM trucks from 1993 and then into Dodge trucks in 1995. Though it has it roots as the New Process 4500 four-speed beginning as early as 1972 in Dodge trucks, its current incarnation as we know it today is quite different.
Identification
The NV 4500 is a top loading five-speed transmission with a cast iron case, aluminum top cover and dual PTO ports. It features all helical gears, and is fully synchronized. The NV4500 has a case length of 12.37" and an extension housing length of 6.5". This housing contains fifth gear. As usual, 2wd style housings are longer.

A unique feature of the NV4500 is its fly-weighted 1st-to-2nd gear synchro assembly, preventing a downshift at excessive revs. Its unique synchro ring composition requires a special synthetic lubricant.

Transfer Case Adaptability
The Chevrolet / GM 4wd version of the NV4500 can be adapted to the Jeep:

Dana 300, 1980-1986
Adaptability to the NP231 transfer case can be acheived when using a Dodge 4wd style tailhousing. However, a change of mainshaft or transfer case input shaft will often be required due to spline count.

Engine Compatibility and Adaptability
The NV4500 is found in GMC & Dodge trucks. The bellhousing pattern for 1993-1994 GM versions is unique from the later (1995-) GM and Dodge units. The 1993 and 1994 Chevy versions have a lower first gear of 6.34:1 and an unsynchronized reverse gear. Transmissions after this period have a higher 5.61 low ratio and reverse gear synchronization.

Input shafts for the GM and Dodge units have 10 splines with 1-1/8" diameter. GM shafts stick out their usual 6-5/8" while the Dodge units are 7-5/8" long.

Make: New Venture Gear
Length: 18.9"
Weight: 195 lbs.
Case: Cast Iron
Top Cover: Aluminum
PTO Ports: Both Sides
Gearing: 6.34, 3.44, 1.71, 1, .73, R 6.34 or,
5.61, 3.04, 1.67, 1, .74, R 5.61


* Just a note... only the 1994-1997 Dodge 2wd version of this transmission has provisions for a mechanical speedometer. The tailhousing of this version is 13 inches long.

**Avoid the HD version that came with the V-10s or Diesels... these have an input shaft that is 10 spline 1 1/4 diameter