YUANJIAN MACHINERY / TECHNICAL LIBRARY
CAT 320D: One Track Slow or Weak
Separate track-side observations, travel controls, hydraulic components and final drive.
One slow track is not automatically a failed travel motor
A used CAT 320D that pulls to one side or has one weak track needs the affected side, direction and operating conditions identified first. External resistance, the control path, travel hydraulic components and the final drive belong to different parts of the investigation. “Left track slow” is useful evidence; “replace the left motor” is already a repair decision that needs testing.
Record the difference without creating a dangerous test
- Identify left/right from the operator’s forward-facing convention and explain the machine orientation in the video.
- Record whether the behavior occurs in forward, reverse or both, on comparable ground and with the same speed mode.
- From a safe position, note visible track obstruction, damaged shoes, leakage or abnormal noise; use the OMM for inspection conditions.
- Do not improvise a raised-track test, brake release, hose swap or test-point connection. A qualified technician must choose and perform the matched procedure.
Which reference topics help separate the causes?
| Reference topic | Why it is relevant |
|---|---|
| Travel motor | Explains hydraulic-to-mechanical operation; does not alone prove the motor is the cause. |
| Parking brake and brake valve | These have separate functions that must be identified in the correct system. |
| Straight-travel valve and travel circuit | Shows how travel is integrated with the wider hydraulic/control system. |
| Final drive | Mechanical reduction and its condition are distinct from the hydraulic motor. |
The inspected training reference separates the 320D-329D travel section from the 330D/336D section. Before a technician applies a check, match the serial number and the actual installed motor/final-drive identification. Undercarriage photos support the discussion but cannot establish internal hydraulic leakage or gear condition.
Inside the reference: verified index extract
CAT 320D-336D / Travel system & final drive
Training reference / different model sections. 59 pages in the local PDF; page numbers below refer to this file, not every edition.
- Travel components
- p. 6
- 320D-329D travel motor
- p. 15
- Travel parking brake
- p. 24
- 320D travel brake valve
- p. 26
- Straight-travel valve
- p. 51
- Final drive
- p. 55
Reference on opening chapter: SCRV1852 (travel section)
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CAT 320D slow or weak hydraulics · Testing and adjustment references
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Public pages contain original YUANJIAN explanations and selected catalogue metadata. Complete documents are supplied only where available, applicable and permitted. Manufacturer rights remain with their owners; YUANJIAN is not a Caterpillar-authorized service center. These indexed collections can combine engine and machine chapters, languages and revisions. Confirm the complete machine serial number, engine identity and the current procedure before repair.
Five-year guidance covers operation, maintenance questions and troubleshooting communication. It is not a five-year machine warranty and does not include free parts, consumables, freight, on-site labor or repairs. Qualified technicians must perform pressure tests, adjustments, lifting and disassembly using the serial-specific service instructions.