Testing and Adjusting 784C and 785C Off-Highway Truck/Tractors Power Train. Transmission Troubleshooting, страница 2

Probable Cause

• Broken components in the transfer gears or in the transmission

Problem: Aluminum particles are found.

Probable Cause

• Worn housings, load pistons, or selector pistons in the pressure control valve

Check: Check the parts inside the transmission case.

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Illustration 5	g00290399
(10) Transmission drain plugs

Remove plugs (10) in the bottom of the transmission case. This will drain all the oil out of the transmission and the transfer gears. Measure the total amount of the oil that is removed at both plugs. Inspect the oil for foreign material.

Problem: More than 76 L (20 US gal) of oil are drained from the transmission and the transfer gears.

Probable Cause

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Illustration 6	g00290397
Lower right side of the transmission case (8) Magnetic screens inside the case

• Restriction in magnetic screens (8)
• Failure of the transmission scavenge pump section
• Too much leakage in a clutch of the transmission

Problem: Rubber particles are found.

Probable Cause

• Seal failure

Problem: Black coarse material is found.

Probable Cause

• Worn clutches in the transmission
• Failure of a thrust disc

Problem: Thin strands that are elastic are found.

Probable Cause

• Worn clutches in the transmission

Problem: Iron chips or steel chips are found.

Probable Cause

• Broken components in the transfer gears or in the transmission

Problem: Aluminum particles are found.

Probable Cause

• Worn housings, worn load pistons, or worn selector pistons in the pressure control valve

Check: Check the parts inside the transmission section of the hydraulic tank.

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Illustration 7	g00367725
(11) Transmission section of the hydraulic tank

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Illustration 8	g00373873
(12) Suction screen

Drain the oil from the transmission section of the hydraulic tank (11). Inspect the bottom of the oil tank for debris. Remove the suction screen (12) for the transmission gear pump. Clean the suction screen (12) .

Problem: Rubber particles are found.

Probable Cause

• Seal failure
• Hose failure

Problem: Shiny steel particles are found.

Probable Cause

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Illustration 9	g00367714
Transmission gear pump (3) Transmission scavenge pump section (4) Transmission lubrication section of the oil pump (5) Transmission charging pump section

• There is a mechanical failure of the transmission scavenge pump section (3) .

Problem: Black coarse material is found.

Probable Cause

• Worn clutches in the transmission
• Failure of a thrust disc

Problem: Thin strands that are elastic are found.

Probable Cause

• Worn clutches in the transmission

Problem: Aluminum particles are found.

Probable Cause

• Worn housings, worn load pistons, or worn selector pistons in the pressure control valve

Note: If any of the particles that are listed in the checks are found during a visual check, all the components of the transmission systems must be cleaned. Do not use any damaged parts. Damaged parts must be removed and new parts must be installed.