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CAT 939C Track Loader Overview
The Caterpillar 939C is a compact track loader introduced in the late 1990s, designed for grading, loading, and light dozing. Powered by a 4-cylinder turbocharged diesel engine producing around 80 horsepower, the 939C features hydrostatic drive, a sealed and lubricated undercarriage, and a rated operating weight of approximately 16,000 pounds. It was part of CAT’s effort to modernize its smaller crawler loaders with improved operator comfort and hydraulic responsiveness.
Caterpillar Inc., founded in 1925, has long been a leader in earthmoving equipment. The 939C was positioned between the smaller 933 and the heavier 953, offering versatility for contractors working in confined spaces or soft ground conditions. Thousands of units were sold globally, with strong adoption in agriculture, landscaping, and utility work.
Unusual Modifications and Field Adaptations
A photograph surfaced showing a 939C outfitted with swamp tracks, a rear-mounted forklift, and a front loader bucket—an unconventional configuration that sparked curiosity. The machine appeared to be operating in a lettuce field, suggesting it was adapted for agricultural harvesting and truck loading.
Key modifications included:
Terminology Notes
Adapting a track loader for agricultural use requires careful attention to balance and hydraulic flow. Adding a rear forklift shifts the center of gravity, potentially increasing tip risk. However, the extended track length and swamp shoes may counteract this by improving stability.
Operators must also consider:
In California’s Salinas Valley, a grower once retrofitted a CAT 931 with a rear-mounted crate handler and swamp tracks to harvest romaine lettuce. The machine operated in tandem with field trucks, reducing labor and increasing throughput. Though not factory-approved, the setup proved effective for seasonal use and was rebuilt annually to meet changing crop layouts.
Recommendations for Custom Builds
The modified CAT 939C track loader with swamp tracks and a rear forklift is a testament to agricultural ingenuity. While not a factory build, it demonstrates how standard equipment can be repurposed for niche tasks like lettuce harvesting. With proper engineering and safety checks, such adaptations can extend machine utility and reduce labor costs in specialized operations.
The Caterpillar 939C is a compact track loader introduced in the late 1990s, designed for grading, loading, and light dozing. Powered by a 4-cylinder turbocharged diesel engine producing around 80 horsepower, the 939C features hydrostatic drive, a sealed and lubricated undercarriage, and a rated operating weight of approximately 16,000 pounds. It was part of CAT’s effort to modernize its smaller crawler loaders with improved operator comfort and hydraulic responsiveness.
Caterpillar Inc., founded in 1925, has long been a leader in earthmoving equipment. The 939C was positioned between the smaller 933 and the heavier 953, offering versatility for contractors working in confined spaces or soft ground conditions. Thousands of units were sold globally, with strong adoption in agriculture, landscaping, and utility work.
Unusual Modifications and Field Adaptations
A photograph surfaced showing a 939C outfitted with swamp tracks, a rear-mounted forklift, and a front loader bucket—an unconventional configuration that sparked curiosity. The machine appeared to be operating in a lettuce field, suggesting it was adapted for agricultural harvesting and truck loading.
Key modifications included:
- Swamp Tracks: Extra-wide low-ground-pressure tracks designed for soft terrain. These tracks reduce soil compaction and improve flotation in muddy fields.
- Rear Forklift Attachment: Mounted in place of the ripper, likely used to carry pallets or stack produce. This setup is rare on track loaders but feasible with custom brackets.
- Loader Bucket with Quick Coupler: Allows rapid switching between bucket and forks, enhancing versatility during harvest operations.
Terminology Notes
- Swamp Tracks: Wide track shoes designed to distribute weight over a larger area, reducing ground pressure.
- Quick Coupler: A hydraulic or mechanical device that allows fast attachment changes without manual pin removal.
- High-Drive Undercarriage: A design where the final drive is elevated above the track frame, improving durability and serviceability.
Adapting a track loader for agricultural use requires careful attention to balance and hydraulic flow. Adding a rear forklift shifts the center of gravity, potentially increasing tip risk. However, the extended track length and swamp shoes may counteract this by improving stability.
Operators must also consider:
- Hydraulic Flow Requirements: Forklift functions may require auxiliary hydraulics or diverter valves.
- Visibility and Control: Rear-mounted attachments reduce rearward visibility and may require camera systems or spotters.
- Maintenance Access: Custom mounts can obstruct access to service points, complicating routine maintenance.
In California’s Salinas Valley, a grower once retrofitted a CAT 931 with a rear-mounted crate handler and swamp tracks to harvest romaine lettuce. The machine operated in tandem with field trucks, reducing labor and increasing throughput. Though not factory-approved, the setup proved effective for seasonal use and was rebuilt annually to meet changing crop layouts.
Recommendations for Custom Builds
- Consult Structural Engineers: Ensure frame integrity and load distribution are safe.
- Use Modular Attachments: Design mounts that can be removed or swapped easily.
- Document Modifications: Maintain records for safety inspections and resale value.
- Test Stability on Slopes: Before field deployment, verify tipping thresholds under load.
The modified CAT 939C track loader with swamp tracks and a rear forklift is a testament to agricultural ingenuity. While not a factory build, it demonstrates how standard equipment can be repurposed for niche tasks like lettuce harvesting. With proper engineering and safety checks, such adaptations can extend machine utility and reduce labor costs in specialized operations.
