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The Legacy of Funk Manufacturing and the Reversomatic Line
Funk Manufacturing, founded in the early 20th century in Coffeyville, Kansas, built its reputation on durable transmissions for agricultural and industrial equipment. By the 1960s, Funk had become a go-to supplier for OEMs needing rugged, torque-rich gearboxes. Their Reversomatic transmission series was designed specifically for applications requiring shuttle shift capability—such as drill rigs, loaders, and forestry machines—where frequent forward-reverse transitions are essential.
The Reversomatic system integrates a torque converter with a shuttle clutch pack, allowing smooth directional changes without manual clutching. This design became popular in Texoma drill rigs and other utility platforms throughout North America. While Funk was eventually acquired by John Deere Power Systems, their transmissions remain in service decades later, often outlasting the machines they were installed in.
Terminology Clarification
In one case involving a Texoma 270 drill rig powered by a Ford 300 inline-six engine, the operator noticed that the transmission would only engage at extremely low RPMs. Both forward and reverse gears were affected, suggesting the issue was not isolated to a single clutch pack or linkage. The transmission had recently been rebuilt, and all break-in procedures—including fluid changes and warm-up cycles—had been followed.
This behavior raised concerns about hydraulic pressure thresholds, governor settings, and possible internal bypassing in the torque converter.
Potential Causes and Diagnostic Pathways
Delayed engagement in torque converter-equipped transmissions can stem from several sources:
Governor and Hydraulic Control Considerations
Many Funk transmissions rely on engine-driven hydraulic pumps to supply pressure to the shuttle clutch packs. These systems often include a governor that modulates engagement based on RPM. If the governor is stuck, misadjusted, or bypassed, it may prevent clutch engagement until the engine drops to idle, where pressure spikes briefly due to reduced flow demand.
In older rigs, governors are mechanical and prone to wear. Springs may weaken, weights may stick, and seals may leak. Replacing or rebuilding the governor can restore proper modulation, allowing engagement across a broader RPM range.
Fluid Viscosity and Seasonal Effects
Transmission fluid viscosity plays a critical role in engagement timing. In colder climates like Saskatchewan, where this rig was operating, fluid thickens and resists flow. If the wrong fluid grade is used—such as a high-viscosity hydraulic oil instead of ATF or low-viscosity synthetic—the converter may struggle to build pressure until the engine slows.
Operators in northern regions often preheat their rigs or switch to synthetic blends during winter. A 2012 study by the Canadian Construction Association found that improper fluid selection accounted for 18% of cold-weather transmission failures in mobile equipment.
Torque Converter Internal Issues
If the torque converter itself was improperly rebuilt or has internal leakage, it may fail to transmit sufficient torque at higher RPMs. Common failure points include:
Control Linkage and Operator Feedback
Although linkage was dismissed as a cause, it’s worth noting that even minor misalignments can affect engagement feel. If the control lever doesn’t fully seat the spool valve, pressure may bleed off. In one anecdote from a forestry crew in British Columbia, a Funk-equipped loader refused to engage forward gear until the operator discovered a bent linkage rod caused by a fallen branch. A $12 part had sidelined a $90,000 machine.
Recommendations and Next Steps
To resolve delayed engagement in a Funk Reversomatic transmission, consider the following steps:
Conclusion
The Funk Reversomatic transmission remains a robust and serviceable component in legacy drill rigs and industrial platforms. While its design is mechanically sound, age, climate, and rebuild quality all influence performance. Delayed engagement at higher RPMs is often a symptom of hydraulic modulation issues, not mechanical failure. With methodical diagnostics and attention to fluid dynamics, even obscure problems can be resolved—keeping these vintage machines drilling, loading, and hauling for years to come.
Funk Manufacturing, founded in the early 20th century in Coffeyville, Kansas, built its reputation on durable transmissions for agricultural and industrial equipment. By the 1960s, Funk had become a go-to supplier for OEMs needing rugged, torque-rich gearboxes. Their Reversomatic transmission series was designed specifically for applications requiring shuttle shift capability—such as drill rigs, loaders, and forestry machines—where frequent forward-reverse transitions are essential.
The Reversomatic system integrates a torque converter with a shuttle clutch pack, allowing smooth directional changes without manual clutching. This design became popular in Texoma drill rigs and other utility platforms throughout North America. While Funk was eventually acquired by John Deere Power Systems, their transmissions remain in service decades later, often outlasting the machines they were installed in.
Terminology Clarification
- Torque converter: A fluid coupling between the engine and transmission that multiplies torque and allows slippage at low speeds.
- Shuttle clutch: A hydraulic clutch pack that enables forward and reverse gear engagement.
- Governor: A device that regulates engine or hydraulic system speed based on load or RPM.
- Linkage: Mechanical connections between control levers and transmission components.
- Break-in procedure: A controlled operating period after rebuild to seat components and ensure proper lubrication.
In one case involving a Texoma 270 drill rig powered by a Ford 300 inline-six engine, the operator noticed that the transmission would only engage at extremely low RPMs. Both forward and reverse gears were affected, suggesting the issue was not isolated to a single clutch pack or linkage. The transmission had recently been rebuilt, and all break-in procedures—including fluid changes and warm-up cycles—had been followed.
This behavior raised concerns about hydraulic pressure thresholds, governor settings, and possible internal bypassing in the torque converter.
Potential Causes and Diagnostic Pathways
Delayed engagement in torque converter-equipped transmissions can stem from several sources:
- Low hydraulic pressure due to worn pump or clogged filters
- Faulty governor not allowing sufficient modulation at higher RPMs
- Incorrect fluid viscosity or contamination
- Internal leakage in clutch packs or converter housing
- Misadjusted or binding control linkage
Governor and Hydraulic Control Considerations
Many Funk transmissions rely on engine-driven hydraulic pumps to supply pressure to the shuttle clutch packs. These systems often include a governor that modulates engagement based on RPM. If the governor is stuck, misadjusted, or bypassed, it may prevent clutch engagement until the engine drops to idle, where pressure spikes briefly due to reduced flow demand.
In older rigs, governors are mechanical and prone to wear. Springs may weaken, weights may stick, and seals may leak. Replacing or rebuilding the governor can restore proper modulation, allowing engagement across a broader RPM range.
Fluid Viscosity and Seasonal Effects
Transmission fluid viscosity plays a critical role in engagement timing. In colder climates like Saskatchewan, where this rig was operating, fluid thickens and resists flow. If the wrong fluid grade is used—such as a high-viscosity hydraulic oil instead of ATF or low-viscosity synthetic—the converter may struggle to build pressure until the engine slows.
Operators in northern regions often preheat their rigs or switch to synthetic blends during winter. A 2012 study by the Canadian Construction Association found that improper fluid selection accounted for 18% of cold-weather transmission failures in mobile equipment.
Torque Converter Internal Issues
If the torque converter itself was improperly rebuilt or has internal leakage, it may fail to transmit sufficient torque at higher RPMs. Common failure points include:
- Worn stator bearings
- Cracked turbine fins
- Damaged one-way clutch
- Improper clearance between impeller and turbine
Control Linkage and Operator Feedback
Although linkage was dismissed as a cause, it’s worth noting that even minor misalignments can affect engagement feel. If the control lever doesn’t fully seat the spool valve, pressure may bleed off. In one anecdote from a forestry crew in British Columbia, a Funk-equipped loader refused to engage forward gear until the operator discovered a bent linkage rod caused by a fallen branch. A $12 part had sidelined a $90,000 machine.
Recommendations and Next Steps
To resolve delayed engagement in a Funk Reversomatic transmission, consider the following steps:
- Verify fluid type and temperature suitability
- Inspect and clean hydraulic filters and screens
- Test governor operation and replace if necessary
- Measure hydraulic pressure at clutch ports during engagement
- Confirm torque converter rebuild quality and internal clearances
- Check linkage travel and spool valve seating
Conclusion
The Funk Reversomatic transmission remains a robust and serviceable component in legacy drill rigs and industrial platforms. While its design is mechanically sound, age, climate, and rebuild quality all influence performance. Delayed engagement at higher RPMs is often a symptom of hydraulic modulation issues, not mechanical failure. With methodical diagnostics and attention to fluid dynamics, even obscure problems can be resolved—keeping these vintage machines drilling, loading, and hauling for years to come.
