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The John Deere 555A and Its Place in Crawler Loader History
The John Deere 555A crawler loader was introduced in the late 1970s as part of Deere’s push to modernize its mid-range tracked equipment. Built in the Dubuque Works facility, the 555A was designed to bridge the gap between smaller dozers and full-sized loaders. With an operating weight around 16,000 pounds and a 4-in-1 bucket option, it became a favorite among contractors for site prep, landfill work, and general-purpose loading.
John Deere, founded in 1837, had by the 1980s become one of the top three manufacturers of construction equipment in North America. The 555A was part of a broader strategy to offer versatile, hydraulically driven machines that could handle both digging and lifting tasks. Though production of the 555A ceased in the early 1990s, thousands were sold across the U.S., and many remain in service today.
Symptoms of Hydraulic and Transmission Failure
A common issue with aging 555A units is the simultaneous loss of hydraulic function and drive capability. When the engine runs but the machine won’t move and the loader arms remain lifeless, the problem often lies in the torque converter assembly or its associated drive components.
Terminology:
Root Cause and Mechanical Breakdown
Upon inspection, the spider gear coupling was found to be completely stripped. All gear teeth were broken off, and rubber isolators were shredded. This coupling failure meant the torque converter wasn’t being driven at all, resulting in zero hydraulic pressure and no transmission engagement.
Compounding the issue, the top bolts securing the engine to the converter housing were loose, leaving a visible gap. This misalignment likely contributed to the destruction of the coupling, as vibration and uneven torque loads can rapidly wear aluminum components.
A deeper inspection revealed:
A father-son team in Alabama purchased a 555A from a landfill for $3,100, hoping to revive it on a budget. After freeing the engine with penetrating oil and installing new injectors, they were thrilled to hear it run. But the joy was short-lived when the machine refused to move or lift.
They fabricated custom loader supports from 3-inch square tubing and used a farm jack to begin engine removal. Despite missing bolts and decades of grime, they extracted the engine in a single afternoon. However, attempts to remove the torque converter were met with resistance. Only after revisiting the service manual did they realize bolts hidden beneath the control valve housing were still holding the converter in place.
This moment of clarity prevented further damage and highlighted the importance of proper documentation—even for seasoned mechanics.
Parts Availability and Cost Considerations
One of the biggest challenges in restoring a 555A is sourcing parts. Many torque converter components, including the spider gear and rubber isolators, are obsolete. Some parts are available used, but prices can be steep:
To avoid similar failures, operators should:
Back in the 1990s, Deere dealers reported that the 555A was costly to repair but beloved by owners. Its balance of weight, horsepower, and hydraulic capacity made it ideal for small contractors. However, the powershift transmission and torque converter were known weak points, especially when neglected.
According to a 2022 survey of vintage crawler loader owners, 555A units still in operation had an average age of 38 years, with most failures related to hydraulic or transmission systems. Owners cited parts availability and documentation as the biggest hurdles to restoration.
Conclusion
The John Deere 555A remains a capable machine when properly maintained, but its age and design quirks demand careful diagnostics. A stripped spider gear coupling can render the loader immobile and hydraulically dead, but with patience, documentation, and a bit of ingenuity, it’s possible to bring these iron workhorses back to life. Whether for personal use or resale, the value of a 555A lies not in its sticker price, but in the work it can still perform.
The John Deere 555A crawler loader was introduced in the late 1970s as part of Deere’s push to modernize its mid-range tracked equipment. Built in the Dubuque Works facility, the 555A was designed to bridge the gap between smaller dozers and full-sized loaders. With an operating weight around 16,000 pounds and a 4-in-1 bucket option, it became a favorite among contractors for site prep, landfill work, and general-purpose loading.
John Deere, founded in 1837, had by the 1980s become one of the top three manufacturers of construction equipment in North America. The 555A was part of a broader strategy to offer versatile, hydraulically driven machines that could handle both digging and lifting tasks. Though production of the 555A ceased in the early 1990s, thousands were sold across the U.S., and many remain in service today.
Symptoms of Hydraulic and Transmission Failure
A common issue with aging 555A units is the simultaneous loss of hydraulic function and drive capability. When the engine runs but the machine won’t move and the loader arms remain lifeless, the problem often lies in the torque converter assembly or its associated drive components.
Terminology:
- Torque Converter: A fluid coupling between the engine and transmission that multiplies torque and allows smooth gear changes.
- Spider Gear Coupling: A flexible drive component that connects the engine flywheel to the torque converter input shaft.
- Hydraulic Pump Drive Gear: A gear mounted on the converter that powers both the transmission pump and loader hydraulic pump.
Root Cause and Mechanical Breakdown
Upon inspection, the spider gear coupling was found to be completely stripped. All gear teeth were broken off, and rubber isolators were shredded. This coupling failure meant the torque converter wasn’t being driven at all, resulting in zero hydraulic pressure and no transmission engagement.
Compounding the issue, the top bolts securing the engine to the converter housing were loose, leaving a visible gap. This misalignment likely contributed to the destruction of the coupling, as vibration and uneven torque loads can rapidly wear aluminum components.
A deeper inspection revealed:
- No metal debris in the transmission filter, suggesting the transmission internals were likely intact.
- The hydraulic pump mounted low on the left side of the converter, driven by a countershaft gear, was not receiving input power.
- The transmission pressure gauge was broken, offering no diagnostic help.
A father-son team in Alabama purchased a 555A from a landfill for $3,100, hoping to revive it on a budget. After freeing the engine with penetrating oil and installing new injectors, they were thrilled to hear it run. But the joy was short-lived when the machine refused to move or lift.
They fabricated custom loader supports from 3-inch square tubing and used a farm jack to begin engine removal. Despite missing bolts and decades of grime, they extracted the engine in a single afternoon. However, attempts to remove the torque converter were met with resistance. Only after revisiting the service manual did they realize bolts hidden beneath the control valve housing were still holding the converter in place.
This moment of clarity prevented further damage and highlighted the importance of proper documentation—even for seasoned mechanics.
Parts Availability and Cost Considerations
One of the biggest challenges in restoring a 555A is sourcing parts. Many torque converter components, including the spider gear and rubber isolators, are obsolete. Some parts are available used, but prices can be steep:
- Rubber isolators: $24 each × 20 units = $480
- Pump drive gear: Nearly the cost of the entire machine
- Rebuilt torque converters: Rare and expensive
- Search salvage yards specializing in Deere equipment.
- Contact torque converter rebuild shops with experience in vintage machinery.
- Consider fabricating replacement couplings if OEM parts are unavailable.
To avoid similar failures, operators should:
- Regularly inspect engine-to-converter mounting bolts for tightness.
- Monitor hydraulic pressure gauges and replace broken units.
- Change transmission and hydraulic filters every 500 hours.
- Use high-quality hydraulic fluid and check for water contamination.
- Check for movement in the converter housing while cranking.
- Inspect the bottom plug of the converter housing for debris.
- Verify pump engagement by checking case drain flow.
Back in the 1990s, Deere dealers reported that the 555A was costly to repair but beloved by owners. Its balance of weight, horsepower, and hydraulic capacity made it ideal for small contractors. However, the powershift transmission and torque converter were known weak points, especially when neglected.
According to a 2022 survey of vintage crawler loader owners, 555A units still in operation had an average age of 38 years, with most failures related to hydraulic or transmission systems. Owners cited parts availability and documentation as the biggest hurdles to restoration.
Conclusion
The John Deere 555A remains a capable machine when properly maintained, but its age and design quirks demand careful diagnostics. A stripped spider gear coupling can render the loader immobile and hydraulically dead, but with patience, documentation, and a bit of ingenuity, it’s possible to bring these iron workhorses back to life. Whether for personal use or resale, the value of a 555A lies not in its sticker price, but in the work it can still perform.
