08-24-2025, 06:16 PM
The History of Pettibone and the Carry-Lift Series
Pettibone, founded in Chicago in 1881, began as a manufacturer of railroad and material handling equipment. By the mid-20th century, the company had expanded into rough-terrain forklifts and telehandlers, carving out a niche in industries like lumber, mining, and construction. The Carry-Lift series, introduced in the 1960s, was designed to handle heavy loads in uneven terrain, offering robust lifting capacity and mechanical simplicity.
The Carry-Lift 6-33, a model from the 1970s, featured a 6,000 lb lifting capacity and a 33-foot reach. It was powered by a diesel engine—often a Detroit Diesel 3-53 or Perkins—and paired with a Funk Reverse-O-Matic transmission. Thousands of units were sold across North America, particularly to logging operations and municipal fleets. Its rugged frame and mechanical drivetrain made it a favorite among operators who valued durability over finesse.
Understanding the Funk Reverse-O-Matic Transmission
The Funk Reverse-O-Matic transmission, commonly found in older telehandlers and industrial tractors, is a hydraulic shift transmission designed for forward and reverse operation without clutching. It uses planetary gear sets and hydraulic clutches to engage drive modes.
Terminology:
Common Symptoms and Diagnostic Pathways
A frequent issue with aged Carry-Lift units is the transmission becoming stuck in reverse. This can occur after long periods of inactivity, especially in humid climates where condensation leads to internal corrosion.
Diagnostic steps:
Field Anecdote from Florida
In Tallahassee, a small contractor relied on a 1970s Carry-Lift 6-33 for moving concrete forms and steel beams. After months of inactivity, the machine was started for a new job but remained locked in reverse. The owner, familiar with the machine’s quirks, suspected the Funk transmission. After ruling out linkage and fluid issues, he removed the control valve and found a varnish-like residue from old hydraulic fluid. A thorough cleaning and fluid flush restored normal operation.
Interestingly, the contractor later installed a magnetic heater pad on the transmission housing to prevent moisture buildup during storage—a simple but effective solution.
Preventive Maintenance and Upgrade Suggestions
To keep the Funk Reverse-O-Matic transmission functioning reliably:
While the Carry-Lift 6-33 is no longer in production, Pettibone continues to manufacture telehandlers and material handlers under the Extendo and Traverse series. These modern machines feature Tier 4 Final engines, joystick controls, and load-sensing hydraulics. However, many operators still prefer the mechanical simplicity of older models for low-speed, high-torque tasks.
Performance comparison:
Conclusion
The Pettibone Carry-Lift 6-33 and its Funk Reverse-O-Matic transmission represent a bygone era of industrial machinery—where steel, hydraulics, and operator intuition ruled the jobsite. While modern machines offer more features, the mechanical integrity and field-serviceability of the 6-33 continue to earn respect. For those maintaining or restoring these units, understanding the transmission’s behavior and keeping the hydraulic system clean are key to preserving its workhorse spirit.
Pettibone, founded in Chicago in 1881, began as a manufacturer of railroad and material handling equipment. By the mid-20th century, the company had expanded into rough-terrain forklifts and telehandlers, carving out a niche in industries like lumber, mining, and construction. The Carry-Lift series, introduced in the 1960s, was designed to handle heavy loads in uneven terrain, offering robust lifting capacity and mechanical simplicity.
The Carry-Lift 6-33, a model from the 1970s, featured a 6,000 lb lifting capacity and a 33-foot reach. It was powered by a diesel engine—often a Detroit Diesel 3-53 or Perkins—and paired with a Funk Reverse-O-Matic transmission. Thousands of units were sold across North America, particularly to logging operations and municipal fleets. Its rugged frame and mechanical drivetrain made it a favorite among operators who valued durability over finesse.
Understanding the Funk Reverse-O-Matic Transmission
The Funk Reverse-O-Matic transmission, commonly found in older telehandlers and industrial tractors, is a hydraulic shift transmission designed for forward and reverse operation without clutching. It uses planetary gear sets and hydraulic clutches to engage drive modes.
Terminology:
- Planetary Gear Set: A gear system consisting of a central sun gear, surrounding planet gears, and an outer ring gear, allowing compact torque multiplication.
- Hydraulic Clutch Pack: A series of friction plates engaged by hydraulic pressure to transmit torque.
- Linkage Assembly: Mechanical rods and levers connecting the operator’s shift lever to the transmission control valve.
Common Symptoms and Diagnostic Pathways
A frequent issue with aged Carry-Lift units is the transmission becoming stuck in reverse. This can occur after long periods of inactivity, especially in humid climates where condensation leads to internal corrosion.
Diagnostic steps:
- Check linkage movement at the transmission housing. Ensure full range of motion and no binding.
- Inspect hydraulic fluid level and condition. Milky or dark fluid may indicate water contamination or breakdown.
- Verify that the control valve actuates properly when the shift lever is moved.
- Examine the transmission’s detent mechanism for wear or misalignment.
Field Anecdote from Florida
In Tallahassee, a small contractor relied on a 1970s Carry-Lift 6-33 for moving concrete forms and steel beams. After months of inactivity, the machine was started for a new job but remained locked in reverse. The owner, familiar with the machine’s quirks, suspected the Funk transmission. After ruling out linkage and fluid issues, he removed the control valve and found a varnish-like residue from old hydraulic fluid. A thorough cleaning and fluid flush restored normal operation.
Interestingly, the contractor later installed a magnetic heater pad on the transmission housing to prevent moisture buildup during storage—a simple but effective solution.
Preventive Maintenance and Upgrade Suggestions
To keep the Funk Reverse-O-Matic transmission functioning reliably:
- Change hydraulic fluid every 500 hours or annually.
- Use a fluid rated for anti-wear and anti-foaming properties.
- Inspect linkage bushings and pivot points quarterly.
- Store the machine indoors or use desiccant breathers on fluid reservoirs.
- Install a transmission temperature gauge to monitor heat buildup.
- Retrofit the shift linkage with sealed rod ends to prevent corrosion.
- Add a spin-on hydraulic filter with a bypass valve for easier servicing.
While the Carry-Lift 6-33 is no longer in production, Pettibone continues to manufacture telehandlers and material handlers under the Extendo and Traverse series. These modern machines feature Tier 4 Final engines, joystick controls, and load-sensing hydraulics. However, many operators still prefer the mechanical simplicity of older models for low-speed, high-torque tasks.
Performance comparison:
- Carry-Lift 6-33: 6,000 lb capacity, mechanical transmission, basic hydraulics
- Traverse T944X: 9,000 lb capacity, electronic controls, 360° visibility, load management system
Conclusion
The Pettibone Carry-Lift 6-33 and its Funk Reverse-O-Matic transmission represent a bygone era of industrial machinery—where steel, hydraulics, and operator intuition ruled the jobsite. While modern machines offer more features, the mechanical integrity and field-serviceability of the 6-33 continue to earn respect. For those maintaining or restoring these units, understanding the transmission’s behavior and keeping the hydraulic system clean are key to preserving its workhorse spirit.
