631E Series II, 633E Series II and 637E Series II Wheel Tractor Power Train Caterpillar

• The engine performance is good.

• The retarder engages properly.

• The retarder releases properly.

• The retarder air pressure is good.

• The retarder oil pressure is good.

Procedure

Illustration 1	g00420584
9U-7400 Multitach Tool Group

Illustration 2	g00635275
Location of Retarder Control Lever

1. Install 9U-7400 Multitach Tool Group on the engine. 9U-7400 Multitach Tool Group can measure engine speed by the use of the photo pickup and reflective tape, a magnetic pickup or a tachometer generator. Instructions for the use of 9U-7400 Multitach Tool Group is in the case.

2. Start the engine.

3. While the transmission control lever is in the NEUTRAL position, make sure that the HIGH IDLE rpm is correct. Also, make sure that the SET POINT rpm is correct. Refer to the Fuel Setting and Related Information Fiche.

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NOTICE
Be sure that the torque converter (transmission) oil does not get too hot.

4. With the engine at HIGH IDLE rpm, pull the retarder control lever to the FULLY ACTIVATED position. The engine rpm must be 1675 ± 100 rpm.

5. Push the retarder control lever back to the RELEASED position. The engine rpm must return to HIGH IDLE rpm.

Results

When the retarder control lever is FULLY ACTIVATED and the engine rpm is too high, one of the following conditions occurred:

• Unavailable air pressure to the supply passage of the retarder air control valve

• The retarder air control valve is worn or the retarder air control valve is damaged. This will allow little air pressure or no air pressure to flow to the air pressure regulator.

• There is wear, damage or incorrect adjustment of the air pressure regulator.

• The hydraulic system has a failure.

When the retarder control lever is in the RELEASED position and the engine rpm is too low, one of the following conditions occurred:

• Wear, damage or incorrect adjustment of the air pressure regulator

• Wear to the retarder air control valve or damage to the retarder air control valve prevents the release of pressure air from the delivery passage.

• Wear to the retarder air control valve or damage to the retarder air control valve slows the release of pressure air from the delivery passage.

• The hydraulic system has a failure.

Note: For more information on the retarder air system, refer to the Systems Operation, Testing and Adjusting, SENR9039, " 631E Series II Wheel Tractor-Scraper, 633E Series II Wheel Tractor-Scraper, 637E Series II Wheel Tractor-Scraper Air Systems and Brakes".