MANIFOLD-EXHAUST 7C7790 - Caterpillar

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Engage the parking brake. Start the engine and run the engine at high idle. Ensure that the oil for the torque converter output is at the normal operating temperature. Refer to Table 3 for normal operating temperature of the machine that is being serviced. This temperature is measured at the torque converter outlet. If Caterpillar Electronic Technician is being used, the oil temperature for the torque converter outlet can be monitored on the screen through Caterpillar ET.
Ensure that the work tool is positioned on the ground.
Reduce the engine speed to low idle.
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Dash PanelLocation of the Digital Tachometer
To ensure that the transmission oil does not overheat, do not keep the torque converter in a full stall condition for more than 30 seconds. After the torque converter stall test, reduce the engine speed to low idle. In order to cool the oil, move the transmission control to the NEUTRAL position and run the engine between 1200 rpm and 1500 rpm.
Fully depress the right side service brake pedal. Shift the transmission direction and speed control to the position that is referred to into the FOURTH SPEED FORWARD position. Hold the right service brake pedal in the depressed position for the duration of the test.Note: Do not use the left brake pedal as a service brake.
Press the governor control pedal to full travel. Allow the engine rpm to stabilize. Then, observe the tachometer. Record the engine rpm. Refer to Table 2 for the correct torque converter stall speed for fourth speed forward. The torque converter outlet pressure should be at least 275 kPa (40 psi).
Set the engine to low idle. Shift the transmission direction and speed control into NEUTRAL position.
The 938G Series II Wheel Loader and the IT38G Series II Integrated Toolcarrier should be tested in First Speed Forward.
With the engine in low idle, shift the transmission direction and speed control to the position that is referred to into the FIRST SPEED FORWARD position.Note: While the parking brake is applied,the following procedure is used in order to engage the power train in the FIRST SPEED FORWARD position. Move the transmission direction and speed control to the NEUTRAL position. Select the FIRST SPEED position on the transmission direction and speed control. Move the transmission and speed control to the FORWARD position. Then move the transmission direction and speed control to the NEUTRAL position, and finally move the transmission direction and speed control back to the FORWARD position.
Slowly depress the governor control pedal to full travel. Allow the engine rpm to stabilize. Then, observe the tachometer. Record the engine rpm. Refer to Table 2 for the correct torque converter stall speed for first speed forward. Record the result. The difference between fourth speed forward and first speed forward should be at least 40 rpm different.
Set the engine to low idle. Shift the transmission direction and speed control into NEUTRAL position.Reference: To check the performance of the Caterpillar 3126B Engine, refer to the following service literature: Specifications, SENR9579, "3126B Engine For Caterpillar Built