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Escaping fluid under pressure, even a pinhole size leak, can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury. Always use a board or cardboard when checking for a leak. |
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Personal injury can result from hydraulic oil pressure and hot oil. Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system. Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand. |
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| NOTICE |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates. |
Introduction
The following tests are used to obtain a scheduled oil sample of the hydraulic system by use of the oil filter bypass valve.
Note: If insufficient oil pressure is measured anywhere in the transmission hydraulic control system, test the pressure of the oil at the oil filter bypass valve. The oil filter can be found in the front right hand side of the machine. The pressure that is measured at the oil bypass valve will be the same pressure that is measured at the transmission hydraulic control relief valve. The pressure at the oil bypass valve is also the transmission pump pressure.
Required Tools
| Required Tools | |||
|---|---|---|---|
| Tooling | Part Number |
Description | Qty |
| A | 169-8373 | Fluid Sampling Bottle | 1 |
Testing Procedure
If the oil becomes contaminated, premature component failure could result. Contaminated oil can also contribute to overheating.
Use the following procedure to determine the contamination of the oil in the hydraulic system.
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| Illustration 1 | g01704373 |
The scheduled oil sample can be taken from the oil bypass valve which is located on the remote oil filter. The oil sampling valve may be located in-line on the inlet side of the transmission oil filter. The oil sampling valve may be located on the inlet side of the torque converter oil filter (1). If your transmission does not have an oil sampling valve, contact your Caterpillar dealer for the appropriate hardware and for the instructions in order to install the oil sampling valve.
- Start the engine. Warm up the oil until the oil reaches 47 °C (116 °F).
- Ensure that the transmission control is in the NEUTRAL position and place the throttle in the LOW IDLE position.
- Remove the cap. Obtain an oil sample from the S·O·S tap with tooling (A) .
- Stop the engine.
- Check the hydraulic filter element for foreign materials.
- Replace the hydraulic filter element.
- Aluminum particles give the indication of torque converter failure or sleeve bearing failure.
- Bronze particles give the indication of sleeve bearing failure.
- Rubber particles give the indication of rubber seal or hose failure.
- Shiny steel particles give the indication of pump failure.
- Iron chips, steel chips or plastic particles give the indication of broken components in transmission or transfer gears.
Note: The transmission oil filter has a bypass valve. A bypass valve allows oil to bypass the oil filter elements when the inlet pressure to the oil filter rises due to a blockage in the oil filter. Any oil that does not go through the filter elements goes directly in the hydraulic circuit. Dirty oil causes restrictions in the valve orifices, the sticking valves, etc.
- Aluminum particles give the indication of torque converter failure or sleeve bearing failure.
If any contamination is found in the filter elements or the screens, all of the components of the transmission hydraulic system must be cleaned. Do not use damaged parts. Any damaged parts must be removed and new parts must be installed.
Refer to Special Publication, PEHP6001, "How To Take A Good Oil Sample". Also, refer to Operation and Maintenance Manual, "SOS Information" and Special Publication, SEBU6250, "SOS Oil Analysis" for additional information about obtaining an oil sample.