Jeep Cherokee (XJ): Description and operation

AX5 manual transmission

DESCRIPTION

The AX5 is a five speed manual transmission with fifth gear being the overdrive range. An adapter housing is used to attach the transmission to the transfer case on 4-wheel drive applications. A standard style extension housing is used for the 2-wheel drive applications.

The shift mechanism is integral to the transmission assembly and mounted in the shift tower portion of the adapter/extension housing (Fig. 1).

GEAR RATIOS

Gear ratios for the AX5 manual transmission are as follows:

•  First gear: 3.93:1
•  Second gear: 2.33:1
•  Third gear: 1.45:1
•  Fourth gear: 1.00:1
•  Fifth gear: 0.85:1
•  Reverse gear: 4.74:1

TRANSMISSION IDENTIFICATION

The AX5 identification code is on the bottom surface of the transmission case near the fill plug (Fig.

2). The first number is year of manufacture. The second and third numbers indicate month of manufacture.

The next series of numbers is the transmission serial number.

OPERATION

The manual transmission receives power through the clutch assembly from the engine. The clutch disc is splined to the transmission input shaft and is turned at engine speed at all times that the clutch is engaged. The input shaft is connected to the transmission countershaft through the mesh of fourth speed gear on the input shaft and the fourth countershaft gear. At this point, all the transmission gears are spinning.

Fig. 1 AX5 Manual Transmission

Fig. 2 Transmission Identification

1 - I. D. CODE ON CASE NEAR DRAIN PLUG

The driver selects a particular gear by moving the shift lever to the desired gear position. This movement moves the internal transmission shift components to begin the shift sequence. 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 the friction cone and eventually will slide over the teeth, locking the gear to the mainshaft, or countershaft, through the synchronizer.

Lubricant

DESCRIPTION

Recommended lubricant for AX5 transmissions is Mopart 75W-90, API Grade GL-3 gear lubricant, or equivalent.

Correct lubricant level is from the bottom edge, to no more than 6 mm (1/4 in.) below the bottom edge of the fill plug hole.

The fill plug is on the passenger side of the adapter housing (Fig. 3). The drain plug is on the bottom of the case.

Approximate dry fill lubricant capacity is:

•  3.3 liters (3.49 quarts) for 4-wheel drive applications.
•  3.5 liters (3.70 quarts) for 2-wheel drive applications.

Fig. 3 Fill Plug Location

1 - FILL PLUG LOCATION