 | |
| Illustration 1 | g00587720 |
Fan drive hydraulic system (1) Fan drive (2) Fan drive motor (3) Makeup valve (4) Pump drive (5) Fan drive pump (6) Oil filter (steering and fan drive) (7) Oil cooler (steering and fan drive) (8) Oil filter (case drain) (9) Hydraulic tank | |
 | |
| Illustration 2 | g00587724 |
Left side view of fan drive lines (3) Makeup valve (4) Pump drive (5) Fan drive pump (8) Oil filter (case drain) (9) Hydraulic tank (10) Solenoid and relief valve | |
 | |
| Illustration 3 | g00587918 |
Rear view of fan drive lines (1) Fan drive (2) Fan drive motor (3) Makeup valve (11) Breather (12) Radiator | |
Oil flows from the fan drive pump (5) through a makeup valve (3) to the fan drive motor (2). Oil flows from the motor through the makeup valve (3). The oil flows from the makeup valve (3) through the oil filter (6) and the oil cooler (7) to the hydraulic tank (9) .
The fan drive motor (2) is a fixed displacement motor. The fan speed is determined by the amount of flow from the fan drive pump (5). The fan drive pump (5) is a variable displacement piston pump that is controlled by the Brake/Cooling ECM.
Case drain oil flows from the fan drive motor (2) and the fan drive pump (5) through a oil filter (8) to the hydraulic tank (9) .
Lubrication oil flows to the fan drive (1) from the supply port of the motor. Lubrication oil flows from the fan drive (1) to the hydraulic tank (9) .
If the supply oil to the fan stops suddenly, the fan and the motor may continue to rotate because of the mass of the fan. The makeup valve (3) allows the oil in the circuit to flow from the return side to the supply side. This prevents a vacuum in the lines on the supply side.
Fan speed is controlled by the Brake/Cooling ECM. Fan speed will vary depending on many inputs.
The minimum fan speed will be 0 rpm. The minimum fan speed will occur when all of the input temperatures are cold.
The following inputs determine the fan speed:
- Jacket water coolant temperature
- Aftercooler coolant temperature
- Transmission lube temperature
- Torque converter outlet temperature
- Brake oil temperature
- Brake status
- Ground speed
| Standard Fan Speed Control Limits (RPM) 96 Inch Fan |
||
| Engine Speed | Non-Retarding Fan Speed Limit | Retarding Fan Speed Limit |
| 1250 or Less | 357 | 575 |
| 1300 | 378 | 575 |
| 1450 | 414 | 575 |
| 1500 | 429 | 575 |
| 1600 | 457 | 575 |
| 1700 | 486 | 575 |
| 1750 | 500 | 575 |
| 1800 | 500 | 575 |
| 1841 | 500 | 575 |
| 1900 | 500 | 575 |
| 1910 | 500 | 575 |
| 1950 | 500 | 575 |
| Standard Fan Speed Control Limits (RPM) 106 Inch Fan |
||
| Engine Speed | Non-Retarding Fan Speed Limit | Retarding Fan Speed Limit |
| 1250 or Less | 321 | 500 |
| 1300 | 334 | 500 |
| 1450 | 414 | 500 |
| 1500 | 386 | 500 |
| 1600 | 411 | 500 |
| 1700 | 437 | 500 |
| 1750 | 450 | 500 |
| 1800 | 450 | 500 |
| 1841 | 450 | 500 |
| 1900 | 450 | 500 |
| 1910 | 450 | 500 |
| 1950 | 450 | 500 |
Refer to Table 1 and Table 2 for the fan speed limits that are based on the temperature sensor inputs, the ground speed and the retarding/braking inputs.
| Engine Fan Control, Non-Retarding Or Retarding Below 4 MPH 96 Inch Fan |
|||||
| Jacket Water Coolant Temperature | Aftercooler Temperature | Trans Lube Temperature | TC Out Temperature | Brake Oil Temperature | Fan Control |
| Priority 1 | 2 | 3 | 4 | 5 | |
| < 88 °C (190 °F) |
< 75 °C (167 °F) |
< 88 °C (190 °F) |
< 88 °C (190 °F) |
< 102 °C (215 °F) |
Off |
| < 99 °C (210 °F) > 88 °C (190 °F) |
< 75 °C (167 °F) |
< 94 °C (201 °F) > 88 °C (190 °F) |
< 94 °C (201 °F) > 88 °C (190 °F) |
< 107 °C (225 °F) > 102 °C (215 °F) |
Modulate By Priority |
| > 99 °C (210 °F) |
> 75 °C (167 °F) |
> 94 °C (201 °F) |
> 94 °C (201 °F) |
> 107 °C (225 °F) |
Limit Chart |
Refer to Table 3. If all of the temperature sensors are below the lower limits, then the fan control is turned off and the fan speed could be as low as 0 rpm. If the temperatures are between the sensor's lower limits and the sensor's upper limits, then the fan speed will be modulated by priority to a fan speed curve that has been preset for each sensor. If any of the sensor's temperatures are above the upper limits, the fan speed will be set to the limits that are shown in Table 1.
| Engine Fan Control, Non-Retarding Or Retarding Below 4 MPH 106 Inch Fan |
|||||
| Aftercooler Temperature | Jacket Water Coolant Temperature | Trans Lube Temperature | TC Out Temperature | Brake Oil Temperature | Fan Control |
| Priority 1 | 2 | 3 | 4 | 5 | |
| < 65 °C (149 °F) |
< 88 °C (190 °F) |
< 88 °C (190 °F) |
< 88 °C (190 °F) |
< 102 °C (215 °F) |
Off |
| < 65 °C (149 °F) |
< 99 °C (210 °F) > 88 °C (190 °F) |
< 96 °C (204 °F) > 88 °C (190 °F) |
< 102 °C (216 °F) > 88 °C (190 °F) |
< 107 °C (225 °F) > 102 °C (215 °F) |
Modulate By Priority |
| < 65 °C (149 °F) |
< 99 °C (210 °F) |
< 96 °C (204 °F) |
< 102 °C (215 °F) |
> 107 °C (225 °F) |
Limit Chart |
| > 65 °C (149 °F) |
> 99 °C (210 °F) |
> 96 °C (204 °F) |
> 102 °C (215 °F) |
> 107 °C (225 °F) |
Limit Chart |
Refer to Table 4. If all of the temperature sensors are below the lower limits, then the fan control is turned off and the fan speed could be as low as 0 rpm. If the temperatures are between the sensor's lower limit and the sensor's upper limit, then the fan speed will be modulated by priority. If all of the temperature sensors are below the upper limit except brake oil temperature, the fan speed will be set to the limits that are shown in Table 2. If any of the temperatures are above the upper limits, the fan speed will be set to the limits that are shown in Table 2.
Note: When the body is being raised, the fan speed will be 200 rpm.
Note: Whenever the aftercooler temperature is above 65 °C (149 °F), the fan speed will be at the full speed.