Manual Transmission/Transaxle: Description and Operation

GENERAL INFORMATION

NV4500 Manual Transmission:

The NV4500 is a five-speed, constant mesh manual transmission. All gear ranges including reverse are synchronized. Fifth gear is an overdrive range with a ratio of 0.75:1. The transmission has a cast iron gear case and aluminum shift cover.

Two versions of the NV4500 are used. A standard duty version is used for 5.2L and 5.9L applications and a heavy duty version for V10 and Cummins diesel applications. Main differences are the larger diameter input shaft, output shaft, and mainshaft fifth gear in the heavy duty model,

The NV4500 is a top loader style transmission. The shift lever is located in a shifter tower which is bolted to the shift cover and operates the shift forks and rails directly. The shift forks and rails are all located within the aluminum cover which is bolted to the top of the gear case.

Tapered roller bearings support the drive gear, mainshaft and countershaft in the gear case. Pilot roller bearings in the drive gear support the forward end of the mainshaft. The mainshaft gears are all supported on caged type roller bearings. Drive gear thrust reaction is controlled by a needle type thrust bearing. The bearing is located at the forward end of the mainshaft.


TRANSMISSION IDENTIFICATION

NV4500 Identification Tag Location:

The NV4500 transmission identification tag is attached to the driver side Power Take-Off (PTO) cover.

The tag provides the transmission model number, build date and part number. Be sure to reinstall the I.D. tag if removed during service. The information on the tag is essential to correct parts ordering.

LUBRICANT LEVEL AND CAPACITY

NV4500 Fill Plug And Drain Bolt:

Required lubricant for the NV4500 is MOPAR Manual Transmission Lubricant, P/N 4637579. This is the only lubricant recommended for use. Dry fill lubricant capacity is approximately 3.78 liters (8 pints). Correct lubricant fill level is to the bottom edge of the fill plug hole. Check fill level only when the transmission is level.

The transmission lubricant is drained through the Power Take-Off (PTO) cover bottom bolt hole. It will be necessary to apply sealer to the bolt threads before installing it during a lubricant change.






GEAR RATIOS


SHIFT PATTERN

NV4500 Shift Pattern:

The NV4500 shift pattern is in a modified H pattern. Overdrive fifth and reverse gears are in line and outboard of the first through fourth gear positions.