725, 730, 735, 740 and 740 EJECTOR Articulated Trucks Power Train Electronic Control System Caterpillar

The hoist lower valve command can be slightly adjusted with the ET. This adjustment will improve the body lowering performance and the snubbing performance. The adjustment of the hoist lower valve will compensate for differences in the valves. The adjustment range is from −5° to +5° with zero as the default. A positive adjustment factor will increase the hoist lower valve command. This will cause the body to come down harder. A negative adjustment factor will decrease the hoist lower valve command. This will cause the body to come down with less impact.

Note: If the adjustment of the hoist lower valve is set too high, then too much oil can be diverted to the hoist system while the hoist system is in the float mode. This could cause the brake oil to heat up at a faster rate. This will also lower retarding capability.

• Adjustment Procedure

Note: Before performing this adjustment procedure, place the hoist lever in the hold position. Place the truck in a stationary position.

1. Place a 3447 kPa (500 psi) pressure gauge on the hoist outlet port.

2. With the body in the down position, move the hoist lever to the hold position.

3. Enter the configuration parameters screen. Select "Service" from the pull-down menu in the ET.

4. Change the adjustment of the hoist lower valve to the desired setting from −5° to +5°.

5. While the engine is operating, move the hoist lever to the float position.

6. Run the engine to HI idle. Verify that the pressure at the hoist outlet port is less than 1724 kPa (250 psi).

Note: If the pressure is greater than 1724 kPa (250 psi) then the adjustment is set too high. This could cause too much oil to be diverted to the hoist valve. The brake oil could overheat, if the operator was driving with the hoist lever in the float position. Lower the setting and repeat the procedure until the pressure is lower than 1724 kPa (250 psi).

Note: Some software versions do not support the adjustment for the hoist lower valve command. If the above tests are completed and the pressures are out of specification, then update the software to the latest software version. See Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program" for information on updating the software.