Manual Transmission/Transaxle: Description and Operation

DESCRIPTION





The NV5600 is a six speed constant mesh manual transmission (Fig. 1). All gear ranges including reverse are synchronized. First and second gears utilize dual cone synchronizers in order to aid shifting. Sixth gear is an overdrive range. The transmission uses cast iron for the gear case and extension/ adapter housing and aluminum for the clutch housing. To drain the trans remove the bottom PTO cover bolt. Fill the trans through the plug to the rear of the PTO cover (Fig. 1). Dry fill is approximately 4.5 liters (9.5 pints) or to the bottom edge of the fill plug hole. The gear ratios are:





OPERATION
The driver selects a particular gear by moving the shift lever to the desired gear position. As the shift lever moves the selected shift rail, the shift fork attached to that rail begins to move. The fork is positioned in a groove in the outer circumference of the synchronizer sleeve. As the shift fork moves the synchronizer sleeve, the synchronizer begins to speed-up or slow down the selected gear (depending on whether we are up-shifting or down-shifting). The synchronizer does this by having the synchronizer hub splined to the mainshaft or the countershaft in some cases, and moving the blocker ring into contact with the gear's friction cone. As the blocker ring and friction cone come together, the gear speed is brought up or down to the speed of the synchronizer. As the two speeds match, the splines on the inside of the synchronizer sleeve become aligned with the teeth on the blocker ring and friction cone and eventually will slide over the teeth, locking the gear to the mainshaft or countershaft through the synchronizer.