OM3241 Operation - Section 32 Operator Cab and Controls Page 32-3 PEDALS DYNAMIC RETARDER PEDAL Dynamic retarder pedal (3, Figure 32-4) is a foot- operated pedal which allows the operator to slow the truck and maintain a safe productive speed without the use of the service brakes. For normal truck oper- ation, only dynamic retarding is used to slow and control the speed of the truck. Refer to Grade/Speed Warning chart to determine the maximum safe truck speeds for descending various grades with a loaded truck. Apply the service brakes only when dynamic retarding requires additional braking force to slow the truck speed quickly and to completely stop the truck.
When dynamic retarding is activated, the engine rpm will automatically go to an advance rpm retard speed setting (usually 1250 rpm, see note below.) Dynamic retarding will be applied automatically if the speed of the truck reaches the predetermined overspeed retard setting. Dynamic retarding is available in FOR- WARD/REVERSE at all truck speeds above 0 kph (mph) but is available in NEUTRAL only when the truck speed is above 5 kph (3 mph). FIGURE 32-4. PEDALS 1. Cab Floor 2. Service Brake Pedal 3. Dynamic Retarder Pedal 4. Throttle Pedal NOTE:
The exact engine speed in retarding may vary (1250 - 1650 rpm) due to the temperature of certain components, This is controlled by the Statex III control system. SERVICE BRAKE PEDAL Service brake pedal (2, Figure 32-4) is a foot-oper- ated pedal which applies the service brakes. NOTE: In some optional installations, the service brake pedal may not be present, because it is incorporated into a single pedal function with retarder pedal (3). THROTTLE PEDAL Throttle pedal (4, Figure 32-4) is a foot-operated pedal which allows the operator to control the engine rpm, depending on the pedal depression.