RADIATOR AR 2Z9158 - Caterpillar

Normal Operation
The position of the left brake pedal is used to determine the impeller clutch pressure. Depressing the left brake pedal reduces the impeller clutch pressure. This reduction will make more engine power available for the implement systems and the steering systems. This available power will reduce the maximum rimpull that will allow the operator to control wheel slippage. Fully depressing the left brake pedal engages the service brakes.Engines that are controlled electronically have a function that is called rimpull. The rimpull allows the operator to select the amount of reduction in the impeller clutch pressure. The pressure is set to one of four preset levels without depressing the left pedal. The amount of impeller clutch pressure is selected by using the reduced rimpull selection switch instead of the left pedal.This feature is enabled when the reduced rimpull ON/OFF switch is in the ON position and the transmission is in first gear forward. When the reduced rimpull selection switch is in the OFF position, the amount of rimpull that is available is 100 percent. If the left pedal is depressed and the reduced rimpull selection switch is in the ON position, then the amount of impeller clutch pressure is reduced to the preset level that is selected. The pressure will be reduced. The amount of the pressure reduction will be determined when the left pedal is depressed.The reduced rimpull selection switch is an input of the control. The reduced rimpull selection switch tells the amount of rimpull that the operator wants to be sent to the control. The control responds by activating the appropriate reduced rimpull mode.The reduced rimpull selection switch is a rotary switch that has four positions. Position 1 (small dot) of the reduced rimpull selection switch is the least amount of impeller clutch pressure. Position 4 (large dot) of the reduced rimpull selection switch is the largest amount of impeller clutch pressure. The control sorts the reduction of rimpull. The control assigns the least amount of rimpull to position 1. The control assigns the largest amount of rimpull to position 4. If the programmed values are corrupted, the control resets the values to the factory settings.The presets at the factory for the impeller clutch pressure include the following percentages of reduction: 40, 55, 70 and 85. The pressures can be changed by using Mode 5 of the Computerized Monitoring System (CMS).Directional Shifts
When the operator requests a directional shift, the transmission control performs the following steps:
If a pressure that is less than the pressure to hold is requested, then the control ignores the left brake pedal position.
When the shift begins, the impeller clutch pressure is reduced and the impeller clutch pressure is maintained at a value of 550 kPa (80 psi).
When the transmission clutches engage, the impeller clutch