Operating Instructions - Section 30 03/13 OM3040 Page 30-10 HAULING 1. Always stay alert! Drive with extreme caution especially when in unfamiliar areas. RETARDER OPERATION Two lists are provided on the retarding capacity decal. One a continuous rating, and the second a short-length rating. Both lists are matched to the truck at maximum Gross Vehicle Weight. 2. Govern the truck speed based on road condi- tions, weather and visibility. 3. Operate the truck with control at all times. The continuous numbers on the chart indicate the combination of speeds and grades which the vehicle can safely negotiate for an unlimited time or distance. 4. Use extreme caution when approaching an intersection.
Maintain a safe distance from oncoming vehicles. The short-length numbers listed on the chart indicate the combination of speeds and grades which the vehicle can safely negotiate for three minutes. These speeds are faster than the continuous values, reflect- ing the thermal capacity of various system compo- nents. System components can accept heating at a higher-than-continuous rate for a short period of time, beyond which the system would become over- heated. 5. Obey all road signs. 6. Always dim high beam headlights before approaching other vehicles in operation. 7. Maintain a safe distance when following another vehicle.
Never approach another vehi- cle from the rear, in the same lane, closer than 15 m (50 ft). When operating on a down grade, stay at least 30 m (100 ft) away. 8. Before starting down a grade, maintain a speed that will insure safe operation and provide effec- tive retarding under all conditions. The short-length rating (sometimes called the "three- minute" limit) will successfully accommodate most downhill loaded hauls. It is necessary to divide haul road grade segment length by allowable speed to determine actual time on grade. If actual time on grade exceeds the allowable amount, the grade will need to be negotiated at the continuous speed.
Ambient temperature, as well as the prior tempera- ture of the brake cooling oil can affect this number (the brake cooling oil could already be above the nor- mal range from recent operating conditions). When descending a known grade with a loaded truck, the operator should adjust the speed of the truck if necessary, to preselect a transmis- sion gear range, so that operation can be main- tained within the speeds listed on the retarding capacity decal located inside the cab on the left front cab post (shown below). Either the retarder control lever or the foot-operated brake pedal can be used to control the speed of the truck.
DO NOT exceed these recommended MAXIMUM speeds when descending grades with a loaded truck. For efficient retarder operation, the operator should: Maintain engine speed between 2000 - 2100 rpm When descending a grade, the operator should apply the retarder lever/foot pedal and observe both the tachometer and the brake oil temperature gauge. Engine speed must be maintained at 2000 - 2100 rpm and the brake oil temperature must be maintained below 120°C (248°F).