INTRODUCTION HAULTRUCK 789D

NEW FEATURES 
The 789D Off-Highway Truck will replace the 789C. The 789D XQ truck is also available and is equipped with additional sound panels. The 789D includes an increased body capacity and payload over the 789C.
The “D” series truck can be equipped with one of the following engines:

The 3516C HD engines are equipped with an Air to Air AfterCooler (ATAAC) to cool the intake air. The 3516B engines are still equipped with a Separate Circuit AfterCooler (SCAC) to cool the intake air.
The machine systems are very similar to the 789C. In addition to the engine, the 789D has received the following updates:
* Electric start option
* Continuous rear axle filtration similar to the 793F
* Transmission size increase similar to 793C
* Improved hydraulic lines routing
* Diagonal ladder (reversible for left or right side access)
* Optional powered stairway
* Optional Object Detection System .

MACHINE WALKAROUND 
The following service points and components are located at the front of the truck:
* Air filter housings (1)
* Dust valves (2)
* Autolube grease reservoir (3)
* VIMS service lamp (4)
* Ground level service panel (5)

NOTE: The 789D can be equipped with a powered access ladder (6). The ladder can be installed on the left or right side of the front bumper. When the powered ladder is on the right side, the diagonal ladder (7) and ground level service panel are installed as shown in this image.
When the powered ladder is on the left side, the diagonal ladder is installed with the base of the ladder at the left side of the bumper, and the ground level service panel is installed on the left side of the bumper.

 Identify ground level service panel components.
Below the VIMS service lamp (1) in the ground level service panel are the following components:
* VIMS service key switch (2) .
* Battery disconnect switch (3) .
* Ladder lamp switch (4) .
* Engine shutdown switch (5) .
* VIMS service connector (6) .
* Engine work light switch (7).

NOTE: The truck can be equipped with an optional transmission shutoff switch and indicator lamp, which are located above the ground level service panel.

Identify service points and components on the right side of the truck
The following service points and components are located on the right side of the truck:
* Steering accumulators (1) .
* Front strut (2) .
* Air start reservoir (only on truck with air starting) (3).
* Transmission lube oil filter (4) .
* Torque converter charging oil filter (5).
* Hydraulic tank (transmission section) (6).
* Hydraulic tank (hoist, converter, and brake oil section) (7) .
* Parking brake release oil filter (8) .
* Hoist cylinder (9) .
* Hoist, converter, and brake oil tank breather (10) .
* Transmission tank breather (11).
* Steering hydraulic tank (12).

Identify service points and components at the rear of the truck.
A cable (not shown) that holds the body up is stored below the rear of the body. Whenever work is to be performed while the body is raised, the safety cable must be connected between the body and the rear hitch (1) to hold the body in the raised position.
A rear axle oil filter (2) removes contaminants from the rear axle housing.
The differential oil level is checked by viewing the oil level sight glass (3). The oil should be level with the bottom of the inspection hole.
An injector bank (4) for the automatic lubrication system is mounted on the top rear of the differential housing.
Above the lubrication injectors is a breather (5) for the rear axle. Inspect the condition of the breather at regular intervals. The breather prevents pressure from building up in the axle housing. Excessive pressure in the axle housing can cause brake cooling
oil to leak through the Duo-Cone seals in the wheel brake assemblies.

Identify service points and components on the left side of the truck
The following service points and components are located on the left side of the truck:
* Hoist cylinder (1) .
* Fuel tank (2) .
* Fuel tank breather (3) .
* Torque converter outlet screen (4) .
* Primary air tank (5) .
* Left strut (6) .
* Air dryer (7) .
* Secondary fuel filters (8) .
* Autolube grease reservoir (9).

Identify TPMS scoreboard
The Truck Payload Measurement System (TPMS) status can be displayed with external loading lamps or an optional scoreboard display (arrow) on the left side of
the cab, as shown in this image. The scoreboard displays the actual payload weight. There is a scoreboard display mounted on each side of the truck. When the truck is equipped with the TPMS external loading lamps, there is one set of lamps on each side of the truck. The lamps are green and red. The lamps inform the loader operator of the loading progress toward a target payload weight. The lamps are active only during the loading cycle and are off at all other times..

 Identify service points and components below the truck bed
The following service points and components are visible from above with the truck bed removed:
* Torque converter housing (1) .
* Hoist pumps (2) .
* Hoist screens (3) .
* Brake retract pump (4) .
* Parking/secondary brake release valve (5) .
* Hydraulic ARC valve (6) ,
* Rear Axle Lubrication (RAXL) pump and motor (7) .
* Transmission (8) .
* Transfer gear (9) .
* Brake makeup tank (10) .
* Rear brake hydraulic cylinders (11) .
* Brake relay valve (12) .
* Front brake hydraulic cylinder (13) .