Rear Axle - 198RBI
DESCRIPTIONThe Rear Beam-design Iron (RBI) axle housing has an iron center casting with axle shaft tubes extending from either side. The tubes are pressed into and welded to the differential housing to form an one-piece axle housing. The axles has semi-floating axle shafts, meaning that loads are supported by the axle shaft and bearings. The axle shafts are retained by bearing retainer plates on the axles, which are bolted to flanges at the outboard end of the axle tubes.
The differential case is a one-piece design. Differential bearing preload and ring gear backlash is adjusted by the use of selective spacer shims. Pinion bearing preload is set and maintained by the use of a collapsible spacer. A differential cover provides a means for inspection and service.
Axles with optional Trac-lok differential have a one-piece differential case, and the same internal components as a standard differential, plus two clutch disc packs.
OPERATION
The axle receives power from the transmission/ transfer case through the rear propeller shaft. The rear propeller shaft is connected to the pinion gear, which rotates the differential through the gear mesh with the ring gear bolted to the differential case. The engine power is transmitted to the axle shafts through the pinion mate and side gears. The side gears are splined to the axle shafts.
STANDARD DIFFERENTIAL
During straight-ahead driving, the differential pinion gears do not rotate on the pinion mate shaft. This occurs because input torque applied to the gears is divided and distributed equally between the two side gears. As a result, the pinion gears revolve with the pinion mate shaft but do not rotate around it (Fig. 1).
When turning corners, the outside wheel must travel a greater distance than the inside wheel to complete a turn. The difference must be compensated for to prevent the tires from scuffing and skidding through turns. To accomplish this, the differential allows the axle shafts to turn at unequal speeds (Fig. 2). In this instance, the input torque applied to the pinion gears is not divided equally. The pinion gears now rotate around the pinion mate shaft in opposite directions. This allows the side gear and axle shaft attached to the outside wheel to rotate at a faster speed.
TRAC-LOK DIFFERENTIAL
This differentials clutches are engaged by two concurrent forces. The first, being the preload force exerted through Belleville spring washers within the clutch packs. The second is the separating forces generated by the side gears as torque is applied through the ring gear (Fig. 3).
This design provides the differential action needed for turning corners and for driving straight ahead during periods of unequal traction. When one wheel loses traction, the clutch packs transfer additional torque to the wheel having the most traction. This differential resists wheel spin on bumpy roads and provides more pulling power when one wheel loses traction. Pulling power is provided continuously until both wheels lose traction. If both wheels slip due to unequal traction, Trac-lok operation is normal. In extreme cases of differences of traction, the wheel with the least traction may spin.