5. Install the transfer case shift linkage, the speedometer cable assembly, and any
electrical connectors or ground straps. Install the transmission shift linkage, if
removed.
6. Fill the transfer case with the proper type and amount of lubricant. Some
manufacturers recommend gear oil, while others specify automatic transmission
fluid. If the transmission and transfer case use the same oil, check the oil level at
the transmission.
7. If necessary, install the skid plate. Then, lower the vehicle.
8. Reconnect the negative battery cable and start the engine. Road test the vehicle
to make sure the linkage adjustments are correct and the transfer case operates
properly. Recheck the oil level after the road test and inspect for leaks.
3.1.1 TROUBLESHOOTING the POWER TAKEOFF
A variety of accessories on heavy-duty tucks and construction equipment require an
auxiliary drive. Auxiliary drive can be sourced directly from the engine or by means of
the transmission or transfer case. Auxiliary drive systems are power takeoffs or PTOs.
When a PTO is coupled to the transmission or transfer case, it is an assembly such as
the two shown in
Figure 8-39
. Vehicles and equipment that have a PTO are wreckers,
fuel tank trucks, dump trucks, cement transit mixers, fire trucks, water well drilling rigs,
auger trucks, aerial bucket trucks, lube trucks, and cranes.
Figure 8-39 - Power takeoffs are used to operate auxiliary equipment.
The PTO is simply a means of using the chassis engine to power accessories,
eliminating the need for an additional auxiliary engine. There are six basic types of
PTOs classified by their installation or drive source:
1. Side mount-is bolted to the side of the main transmission and is the most
common type found on trucks.
2. Split shaft-transmits torque from the chassis driveshaft, is located behind the
transmission and requires special mounting to the chassis frame.
3. Top mount-is usually found mounted to the top of an auxiliary transmission.
4. Countershaft-is mounted behind the transmission and when used replaces the
bearing cap located at the rear of one countershaft on a twin-countershaft
transmission.
NAVEDTRA 14050A
8-45