The History of Fermac and the 750 Series
The Fermac 750 backhoe loader was produced during the mid-1990s by Fermec, a British manufacturer that evolved from Massey Ferguson’s construction equipment division. After Massey Ferguson exited the backhoe market, Fermec continued production under its own name until it was acquired by Terex in the early 2000s. The 750 model was designed as a mid-size backhoe loader, offering a balance of power, maneuverability, and mechanical simplicity for contractors, municipalities, and agricultural users.
Equipped with a Perkins diesel engine and a mechanical or semi-automatic transmission, the Fermac 750 was built to handle trenching, loading, and light excavation tasks. Its popularity in Europe and South Africa stemmed from its affordability and ease of service, especially in regions where dealer support was limited.
Core Specifications and Mechanical Features

• Engine: Perkins 1004-4 or 1004-4T, 4-cylinder diesel
  
• Power Output: Approximately 80–90 HP
  
• Transmission: 4-speed shuttle or powershift, depending on variant
  
• Drive: 2WD standard, 4WD optional (often removed or modified)
  
• Hydraulic System: Shared pump for steering and implement control
  
• Operating Weight: Around 7,500–8,000 kg
  
• Bucket Capacity: 1.0–1.2 cubic meters (loader), 0.2–0.3 cubic meters (backhoe)
  

• No movement in either direction
  
• Clicking sound from solenoids when shifting
  
• Temporary movement after long idle periods
  
• Steering remains functional
  
• Hydraulic implements respond normally
  

• Check transmission oil level using the dipstick near the bellhousing on the left-hand side
  
• Inspect oil color and clarity—reddish fluid indicates ATF or hydraulic oil; milky fluid suggests water contamination
  
• Test forward and reverse solenoids for audible click and voltage
  
• Lift wheels off the ground and observe movement at idle and increased RPM
  
• Turn steering to full lock while engaging drive—if movement occurs, pump output may be marginal
  
• Use a 500 psi gauge to test charge pressure at the transmission valve
  

• Steering and transmission share the same pump
  
• Backhoe and loader functions draw from the main hydraulic circuit
  
• Relief valves regulate pressure across subsystems
  

• Removal of 4WD components due to wear or lack of parts
  
• Replacement of filler hoses with rubber plugs or improvised caps
  
• Bypassed solenoids or manual override switches
  
• Non-OEM hydraulic fluid substitutions
  

• Change transmission fluid every 500 hours
  
• Replace hydraulic filters annually
  
• Inspect solenoid wiring and connectors quarterly
  
• Test charge pump output during each service interval
  
• Use ISO 46 hydraulic oil or ATF as specified by the manufacturer
  
• Keep a log of fluid changes and pressure readings
  

• Transmission control valves
  
• Charge pumps
  
• Solenoids and wiring harnesses
  
• Hydraulic filters and seals
  
• Steering cylinders and linkages
  

The Case 580 SR is a popular tractor loader used in various construction, landscaping, and agricultural tasks. It is known for its durability, powerful engine, and advanced hydraulics. However, like many pieces of heavy machinery, it is prone to issues related to its electronic systems. One of the common problems reported by operators is the malfunction of the hour meter. The hour meter plays a crucial role in tracking the machine's operational hours, which is vital for maintenance schedules and resale value. When the hour meter fails, it can lead to difficulties in tracking usage and performing necessary maintenance at the appropriate times.
In this article, we will delve into the potential causes of hour meter problems on the Case 580 SR, explore troubleshooting methods, and provide solutions for fixing this issue.
Understanding the Importance of the Hour Meter
The hour meter is an essential component in any heavy machinery, including the Case 580 SR. It keeps track of the number of hours the machine has been in operation. This data is crucial for:

1. Scheduled Maintenance: Regular maintenance is key to keeping the machine running efficiently. The hour meter helps operators know when it’s time to change the oil, inspect the engine, or perform other maintenance tasks.
   
2. Warranty and Resale Value: For resale purposes, the number of hours logged on the machine is often one of the most important factors. A malfunctioning hour meter can create uncertainty about the true usage of the machine, which may impact its market value.
   
3. Performance Monitoring: The hour meter can also provide insight into the machine’s performance, helping operators identify if the machine is being overused or if certain systems are not functioning optimally.
   

1. Electrical Connection Issues: The hour meter is typically connected to the electrical system of the machine, often through the alternator or a dedicated sensor. If the electrical connections are loose or corroded, the hour meter may stop working. In some cases, it may record hours intermittently or inaccurately.
   
2. Faulty Hour Meter Itself: Like any mechanical or electronic component, the hour meter itself can wear out or break. Over time, the internal circuitry of the hour meter may fail, leading to an inability to track hours properly.
   
3. Malfunctioning Alternator: In many cases, the hour meter is powered by the alternator. If the alternator is malfunctioning or not generating the correct voltage, it may affect the operation of the hour meter. A drop in power supply can cause the meter to freeze, reset, or fail to record hours.
   
4. Blown Fuse or Relay Issues: The electrical circuits powering the hour meter may rely on a fuse or relay. If either of these components fails, the hour meter will not receive the necessary power to function. A simple fuse replacement might solve the issue.
   
5. Faulty Wiring or Sensor: The sensor that detects the machine’s operation and sends the signal to the hour meter may fail or become disconnected. Wiring issues between the sensor and the meter can also lead to inaccurate readings or complete failure.
   

1. Visual Inspection: Start by performing a visual inspection of the hour meter. Check the display for any obvious signs of damage or malfunction, such as flickering or blank screens. Ensure that the meter is receiving power by observing any lights or indicators that should be active when the machine is in operation.
   
2. Check Electrical Connections: Examine the electrical wiring that connects the hour meter to the alternator, sensor, and power source. Look for any loose or corroded connections. If you find any, clean or tighten the connections and check if the hour meter starts functioning.
   
3. Inspect the Alternator: Check if the alternator is working properly. You can use a multimeter to measure the voltage output of the alternator while the machine is running. A faulty alternator can cause irregularities in the hour meter, so ensuring the alternator is supplying stable power is crucial.
   
4. Test the Fuse and Relays: Inspect the fuses and relays related to the hour meter circuit. Replace any blown fuses and ensure the relays are functioning. Fuses and relays are inexpensive and easy to replace, and addressing this issue can often restore functionality to the meter.
   
5. Check the Hour Meter Itself: If the wiring and electrical components seem to be in good condition, the issue might lie with the hour meter itself. In this case, replacing the meter might be necessary.
   

1. Repair or Replace Electrical Connections: If corrosion or loose connections were the problem, repair them by cleaning the terminals and ensuring a solid connection. It’s advisable to use dielectric grease to prevent future corrosion and ensure a long-lasting connection.
   
2. Replace the Hour Meter: If the hour meter is damaged or has failed entirely, you will need to replace it. Ensure you select a replacement that matches the specifications of the Case 580 SR. Installation typically involves removing the old meter and connecting the new one to the existing wiring.
   
3. Replace the Alternator: If the alternator is found to be faulty, it may need to be repaired or replaced. A functioning alternator is crucial not just for the hour meter, but also for the overall operation of the machine. In some cases, you may need a professional technician to replace or rebuild the alternator.
   
4. Install a New Fuse or Relay: If a blown fuse or faulty relay is the cause, replacing these components is a relatively simple and inexpensive fix. After replacing the fuse or relay, check to ensure that the hour meter is functioning correctly.
   
5. Sensor or Wiring Replacement: If the sensor that detects machine operation is faulty or the wiring is damaged, these components will need to be replaced. Ensure that the new sensor is properly calibrated to work with the hour meter system.
   

1. Regular Inspections: Periodically check the electrical connections and wiring related to the hour meter. Early detection of wear or corrosion can prevent more serious problems later.
   
2. Maintain the Alternator: Keep the alternator in good condition by ensuring it’s properly serviced. A healthy alternator will provide consistent power to the hour meter and other electrical components.
   
3. Use Quality Parts: When replacing any components related to the hour meter, always use high-quality, OEM parts to ensure compatibility and durability.
   
4. Monitor Usage: Regularly monitor the machine’s performance and the hour meter readings. If the readings seem inconsistent, investigate immediately to avoid issues during scheduled maintenance.
   

The Development and Legacy of the 6HK1
The Isuzu 6HK1 is a 7.8-liter inline six-cylinder turbocharged diesel engine developed for medium and heavy-duty commercial applications. Introduced in the early 2000s, it quickly gained traction in vocational trucks, construction equipment, and industrial platforms due to its balance of power, fuel efficiency, and long service intervals. Built with a cast iron block, forged steel crankshaft, and high-pressure common rail fuel injection, the 6HK1 was engineered to meet global emissions standards while maintaining mechanical reliability.
Isuzu’s engine division, with roots dating back to the 1930s, has produced millions of diesel engines for OEMs worldwide. The 6HK1, in particular, became a staple in fleet operations, often exceeding 400,000 miles or 10,000 hours with proper maintenance. It was widely installed in vehicles such as the Isuzu F-Series, Hitachi excavators, and various genset platforms.
Core Specifications and Performance Characteristics

• Displacement: 7.8 liters
  
• Configuration: Inline 6-cylinder
  
• Aspiration: Turbocharged with intercooler
  
• Fuel System: High-pressure common rail
  
• Power Output: 200–300 HP depending on application
  
• Torque: Up to 900 Nm
  
• Emissions: Euro III–V compliant with EGR and DPF options
  
• Compression Ratio: 17.5:1
  
• Oil Capacity: Approximately 24 liters
  
• Service Interval: 500 hours or 15,000 km for oil and filter
  

• Caused by clogged radiators, faulty thermostats, or viscous fan coupling failure
  
• Symptoms: High coolant temperature, loss of power, white smoke
  
• Solution: Replace thermostat, flush cooling system, inspect fan clutch
  

• Often from valve cover gaskets, rear main seals, or turbo oil lines
  
• Symptoms: Visible oil on block, low oil pressure warning
  
• Solution: Replace gaskets with OEM-grade materials, inspect breather system
  

• Blue smoke: Indicates oil burning due to worn valve seals or piston rings
  
• White smoke: Coolant intrusion from head gasket failure
  
• Black smoke: Rich fuel mixture from injector malfunction or EGR clogging
  
• Solution: Compression test, injector balance check, EGR cleaning
  

• Linked to injector wiring faults, sensor failure, or fuel contamination
  
• Solution: Scan for fault codes, test injector resistance, replace fuel filters
  

• Caused by clogged air filters, turbocharger wear, or fuel delivery issues
  
• Solution: Boost pressure test, inspect intercooler, clean intake manifold
  

• Crankshaft position sensor
  
• Camshaft sensor
  
• Boost pressure sensor
  
• Coolant temperature sensor
  
• EGR valve position sensor
  

• Pistons and rings
  
• Main and rod bearings
  
• Gasket set
  
• Oil pump
  
• Timing gears
  
• Injector seals
  

• Change oil and filters every 500 hours or 15,000 km
  
• Inspect coolant system quarterly
  
• Replace fuel filters every 250 hours
  
• Clean EGR valve annually
  
• Scan for fault codes monthly
  
• Use high-quality diesel with low sulfur content
  
• Monitor boost pressure and exhaust backpressure
  

The Bobcat 873 skid steer is a versatile and powerful machine, known for its efficiency in a wide range of construction, landscaping, and agricultural tasks. With its compact design and robust hydraulic system, it can tackle heavy lifting, digging, and moving materials in confined spaces. However, like all heavy machinery, the Bobcat 873 is prone to wear and tear, and one common issue that operators face is oil and fluid leaks.
These leaks can arise from various components and can significantly affect the machine’s performance if left unaddressed. In this article, we will explore the causes, diagnosis, and solutions to oil and fluid leaks in the Bobcat 873 skid steer, offering insights into the potential issues and how to mitigate them.
Understanding the Bobcat 873 Skid Steer
The Bobcat 873 was introduced as part of Bobcat's larger line of skid steers designed for demanding applications. Featuring a rated operating capacity of 1,750 lbs, the 873 has an efficient hydraulic system capable of lifting heavy loads with its vertical lift arms. Over the years, it has become a staple in many construction and agricultural operations due to its ease of maneuverability, powerful hydraulics, and reliability.
Like other Bobcat skid steers, the 873 utilizes hydraulic oil to power the lifting arms, wheels, and various attachments. Given the machine's intense use, its hydraulic system is critical to its performance. A leak in this system, especially in the hydraulic fluid, can cause a loss of power and efficiency, rendering the machine less effective and increasing the risk of further damage.
Common Causes of Oil and Fluid Leaks in Bobcat 873
Oil and fluid leaks in the Bobcat 873 can stem from a variety of sources, with the most common being the hydraulic system. Below are the primary culprits:

1. Hydraulic Hose Damage: Over time, hydraulic hoses can wear out due to the high pressure within the system. These hoses are subject to constant flexing, exposure to extreme temperatures, and friction from surrounding components. A damaged hose can lead to fluid leaks, which can affect the machine’s hydraulic system performance.
   
2. Hydraulic Cylinder Seals: The hydraulic cylinders in the Bobcat 873, responsible for lifting and lowering the arms, are sealed with rubber or synthetic seals that can degrade over time. If these seals are worn, cracked, or damaged, hydraulic fluid can leak from the cylinders, reducing the machine's lifting capacity and efficiency.
   
3. Hydraulic Pump Leaks: The hydraulic pump, which generates the necessary fluid pressure for the hydraulic system, can sometimes develop leaks due to wear or improper maintenance. Fluid leakage from the pump can be caused by faulty seals or gaskets, or the pump's connections may become loose, causing pressure loss.
   
4. Transmission and Engine Oil Leaks: While hydraulic fluid leaks are often the main concern, Bobcat 873 owners also need to be aware of leaks related to the engine and transmission oil. These leaks typically originate from worn seals or gaskets around the engine or transmission housing. As with any heavy machinery, maintaining proper oil levels is crucial to avoid further engine or transmission damage.
   
5. Fluid Reservoir Cap or Drain Plug Issues: Sometimes, the issue may be as simple as a loose or improperly sealed fluid reservoir cap. If the cap isn’t tightly fastened, fluid can leak out, especially when the machine is in motion. Similarly, a loose drain plug can lead to slow, ongoing fluid loss.
   
6. Oil Cooler Leaks: The Bobcat 873, like many skid steers, uses an oil cooler to maintain proper operating temperatures for its hydraulic system. If the cooler becomes damaged or if its seals deteriorate, it can lead to fluid leaks, affecting the system’s performance and causing overheating issues.
   

1. Visual Inspection: Start by thoroughly inspecting the machine’s hydraulic system. Look for any obvious signs of leakage around the hoses, cylinders, and hydraulic pump. Pay close attention to the connections where hoses meet fittings, as these are common leak points.
   
2. Check Fluid Levels: Monitor the fluid levels in the hydraulic reservoir, engine, and transmission. If the levels are dropping significantly without visible signs of leakage, it may indicate an internal leak or an issue with the seals.
   
3. Clean the Area: Clean the machine’s engine and hydraulic system thoroughly to remove any accumulated dirt and grime. This makes it easier to spot new leaks as you operate the machine.
   
4. Operate the Skid Steer: After cleaning, run the skid steer through its normal operational motions. This will pressurize the hydraulic system and may cause hidden leaks to become more visible. Check for fluid pooling on the ground or dripping from various components.
   
5. Pressure Testing: For more advanced diagnostic work, pressure testing of the hydraulic system can be performed. This test can help detect leaks in the hydraulic pump or cylinders that are not readily visible during normal inspection.
   

1. Replace Damaged Hydraulic Hoses: If a hydraulic hose is damaged, it should be replaced with a new, high-quality hose that meets the specifications of the Bobcat 873. Ensure that the new hose is properly installed, with secure fittings and no kinks or twists that could cause further damage.
   
2. Seal or Replace Hydraulic Cylinders: If the hydraulic cylinder seals are the issue, you can either replace the seals yourself (if you have the proper tools and experience) or have the cylinders rebuilt by a professional. In some cases, if the cylinders are extensively damaged, they may need to be replaced entirely.
   
3. Replace Worn Gaskets or Seals: For leaks around the hydraulic pump or the engine and transmission, replace the worn gaskets or seals. Ensure that all parts are compatible with the Bobcat 873 model to prevent future leaks.
   
4. Tighten or Replace the Fluid Reservoir Cap: If the fluid reservoir cap or drain plug is loose or damaged, it can be tightened or replaced to prevent further fluid loss. Always check the cap regularly to ensure a secure fit.
   
5. Repair or Replace the Oil Cooler: If the oil cooler is leaking, it will need to be either repaired or replaced, depending on the extent of the damage. If the cooler is severely damaged, consider investing in a high-quality replacement that fits the Bobcat 873.
   

1. Regular Fluid Checks: Keep track of your fluid levels, and top up or change fluids as necessary. Ensure that the fluids are clean and free from contaminants.
   
2. Routine Inspections: Perform regular inspections of the hydraulic system, engine, and transmission to detect any early signs of wear or leaks. Catching small issues early can prevent more significant problems down the road.
   
3. Use High-Quality Parts: When replacing hoses, seals, and other components, always opt for high-quality, OEM (Original Equipment Manufacturer) parts to ensure proper fitment and durability.
   
4. Service the Machine Regularly: Follow the manufacturer’s service intervals and perform scheduled maintenance to keep the Bobcat 873 in optimal condition.
   

The Caterpillar 242D Skid Steer Platform
The Caterpillar 242D is part of the D-Series skid steer loader family, introduced in the early 2010s to meet growing demand for compact, high-performance machines in construction, landscaping, and utility work. Built in Sanford, North Carolina, the 242D features a vertical lift design, a rated operating capacity of 2,200 lbs, and a turbocharged 74.3-horsepower engine. With over 30,000 units sold globally, the 242D became a popular choice for contractors seeking a balance of power, maneuverability, and hydraulic versatility.
Its drive system includes a chain-case axle assembly, planetary final drives, and sealed bearings designed for long service intervals. However, axle wear and hub seal failure can occur due to high torque loads, contamination, or improper maintenance—especially in machines operating in muddy or abrasive environments.
Symptoms of Axle and Hub Failure
Operators may notice several signs indicating axle or hub issues:

• Oil leaking from the drive hub or axle seal
  
• Grinding or clicking noises during travel
  
• Excessive wheel play or wobble
  
• Reduced traction or uneven drive response
  
• Visible damage to the hub flange or axle shaft
  

1. Lift and Secure the Machine
   • Use jack stands rated for at least 5,000 lbs
     
   • Remove the wheel and clean the hub area thoroughly
     
2. Drain the Hub Oil
   • Remove the fill plug and drain plug
     
   • Inspect the oil for metal shavings or water contamination
     
3. Remove the Drive Hub Cover
   • Unbolt the hub flange using a torque wrench
     
   • Carefully extract the cover to expose the planetary gears
     
4. Extract the Axle Shaft
   • Remove the retaining clip or snap ring
     
   • Slide the axle shaft out of the hub assembly
     
   • Inspect splines for wear or deformation
     
5. Replace Seals and Bearings
   • Install new inner and outer seals using a seal driver
     
   • Replace bearings if pitted or noisy
     
   • Use high-temperature grease rated for gear applications
     
6. Reassemble and Refill
   • Reinstall the axle and hub components
     
   • Torque bolts to manufacturer spec (typically 90–110 ft-lbs)
     
   • Refill with SAE 80W-90 gear oil or CAT TDTO as specified
     
7. Test and Inspect
   

• Run the machine at low speed and check for leaks
  
• Monitor hub temperature and oil level over the next 10 hours
  

• Over-torquing hub bolts, causing flange warping
  
• Reusing old seals, which may not seat properly
  
• Failing to clean mating surfaces, leading to oil leaks
  
• Using incorrect oil viscosity, especially in cold climates
  

• Inspect hub oil every 250 hours
  
• Replace seals every 1,000 hours or when leakage is observed
  
• Avoid high-speed travel over rocky terrain
  
• Clean hubs after operating in mud or sand
  
• Use magnetic drain plugs to detect early wear
  

• Use OEM axle shafts and seals for guaranteed fit
  
• Confirm part numbers using the machine’s serial prefix (e.g., BLN, JAY)
  
• Avoid aftermarket seals unless verified for material compatibility
  
• Order planetary gear kits if gear teeth show pitting or wear
  

The Fiat-Allis FD5 is a mid-sized bulldozer that was built to deliver powerful performance in challenging environments. Introduced in the 1980s, the FD5 is renowned for its robust construction and reliability in heavy-duty earthmoving operations. However, like any machine of its age, the FD5 can experience mechanical issues. One of the common problems that operators face with the FD5 is related to the right steering clutch, which can cause operational difficulties and decrease efficiency if not addressed promptly.
Understanding the Problem: Right Steering Clutch Malfunction
The steering clutch is a critical component in any tracked vehicle, such as bulldozers, excavators, and track loaders. It allows the operator to control the movement and turning of the vehicle by engaging and disengaging the drive to each side of the tracks. When there is an issue with the steering clutch, it can result in the inability to turn the machine properly, making the operation difficult and potentially unsafe.
For the 1984 Fiat-Allis FD5, the right steering clutch issue typically manifests in one of two ways:

1. Incomplete Disengagement: The clutch does not fully disengage, causing the right track to continue moving, even when the steering lever is in the neutral position.
   
2. Excessive Drag or Slipping: The clutch may fail to fully engage, resulting in slipping of the right track, which can lead to inefficient operation and reduced power to that side of the machine.
   

• Low Hydraulic Pressure: The steering clutch system on the FD5 is often hydraulically operated. If there is insufficient hydraulic pressure due to leaks, low fluid levels, or a failing hydraulic pump, the clutch will not function properly.
  
• Worn or Damaged Clutch Plates: Over time, the clutch plates within the steering clutch assembly can wear down, leading to slippage, failure to engage, or incomplete disengagement.
  
• Contaminated or Old Fluid: Hydraulic fluid that has become contaminated or degraded can impair the function of the steering clutch. Fluid should be checked regularly and replaced if necessary to ensure proper hydraulic operation.
  
• Linkage or Control Valve Malfunctions: Problems with the linkage or control valve, which regulates the engagement and disengagement of the clutch, can result in the steering clutch not operating smoothly or effectively.
  
• Internal Wear of the Clutch Assembly: The clutch assembly may experience internal wear or mechanical failure in the form of damaged seals, broken springs, or other worn-out components that prevent it from functioning correctly.
  

1. Check Hydraulic System: Start by inspecting the hydraulic fluid levels and the condition of the hydraulic system. If the fluid is low, add the recommended type of fluid. If the fluid is dirty or contaminated, flush the system and replace the fluid. Inspect the hydraulic pump for signs of damage or wear and ensure there are no leaks in the system.
   
2. Test the Steering Clutch: Test the steering clutch by operating the machine under different conditions. If the right side continues to move even when the steering lever is in the neutral position, this may indicate that the clutch is not disengaging completely.
   
3. Inspect the Clutch Plates: If the clutch continues to slip or drag, remove and inspect the clutch plates for wear and damage. If they appear worn, replacing them may resolve the issue.
   
4. Inspect Linkages and Control Valves: Check the linkage system and the control valve for any signs of malfunction. The linkage should be free of any obstruction or damage, and the control valve should be functioning correctly.
   
5. Conduct a Load Test: If possible, conduct a load test to assess the performance of the right track under operational conditions. This can help identify if the issue lies with the clutch or the overall drive system.
   

• Hydraulic Repairs: If low hydraulic pressure is the root cause of the issue, repairing or replacing any faulty hydraulic components, such as the pump, hoses, or seals, may restore full functionality to the steering clutch.
  
• Clutch Plate Replacement: Worn or damaged clutch plates can be replaced, though this can be a labor-intensive process requiring the removal of the clutch assembly. New clutch plates should be properly installed, and the clutch should be tested before returning the machine to service.
  
• Fluid and System Maintenance: Regular maintenance of the hydraulic fluid is critical to maintaining the function of the steering clutch. Replace the fluid at regular intervals and ensure that it remains free of contaminants. You may also need to replace any seals or gaskets that have become worn.
  
• Adjust Linkages: If the issue stems from malfunctioning or misaligned linkages, these should be adjusted or replaced to restore proper clutch engagement and disengagement.
  
• Control Valve Adjustment or Replacement: A malfunctioning control valve should either be adjusted or replaced. If the valve is clogged or damaged, it may be preventing the proper flow of hydraulic fluid to the clutch system.
  

• Routine Hydraulic System Inspections: Regularly inspect the hydraulic system for leaks and ensure that fluid levels are maintained. Keep an eye on the condition of the hydraulic lines and pump.
  
• Scheduled Maintenance: Follow the manufacturer’s recommended maintenance schedule for the steering clutch and the entire drive system. This will help identify potential issues before they cause serious problems.
  
• Monitor Clutch Performance: Regularly test the performance of the steering clutches under different operating conditions to catch any early signs of trouble.
  

The Ford F-650 Medium-Duty Platform
The Ford F-650 was introduced in 2000 as part of Ford’s medium-duty commercial truck lineup, designed to bridge the gap between light-duty pickups and Class 7 vocational trucks. Built in partnership with Navistar and later produced solely by Ford, the F-650 offered a range of powertrains including the Cummins ISB diesel and Caterpillar 3126, paired with Allison automatic or Eaton manual transmissions. By 2006, the F-650 had become a popular choice for utility fleets, tow operators, and vocational upfits due to its customizable chassis and robust drivetrain.
The 2006 model year featured electronic integration between the engine control module (ECM), transmission control module (TCM), and vehicle interface modules (VIMs), allowing for coordinated shifting, speed sensing, and diagnostic communication. However, this complexity also introduced new failure modes—particularly when wiring integrity or sensor data was compromised.
Symptoms of the Fault
Operators have reported a specific failure pattern:

• Speedometer is non-functional
  
• Transmission fails to shift out of low gear
  
• No diagnostic communication with the transmission module
  
• Engine runs normally but drivetrain behavior is erratic
  
• No visible fault lights on the dash
  

• The VSS, typically mounted on the transmission tailshaft, sends pulses to the ECU
  
• If the sensor fails or wiring is damaged, speed data becomes erratic or absent
  
• Diagnostic code: SAE J1939 code 128 84 02 (engine module reporting VSS data missing)
  

• Medium-duty trucks often suffer from harness degradation due to vibration, heat, and poor repairs
  
• Hand-twisted and taped splices are common in field repairs but prone to failure
  
• A bypassed or corroded wire to the transmission ECU can prevent power delivery
  

• Pin 3 on the transmission ECU is critical for power input
  
• If voltage is absent due to a broken wire or poor splice, the ECU will not boot
  
• Without ECU activation, the transmission remains in default mode
  

• The vehicle interface module (VIMs) coordinates communication between the engine, transmission, ABS, and body control systems
  
• If the VIMs module is misconfigured or missing, modules may not appear in diagnostic scans
  
• Some trucks show a retarder module in the scan despite not having one, indicating software misalignment
  

• Inspect and clean battery terminals thoroughly; poor voltage can disrupt ECU boot
  
• Use a scan tool to verify active modules—if the transmission ECU is missing, check power and ground
  
• Locate the VSS and test for signal output using an oscilloscope or multimeter
  
• Trace wiring from the VSS to the ECU, looking for splices, corrosion, or broken insulation
  
• Confirm power at pin 3 of the transmission ECU; if absent, repair with solder and heat shrink
  
• Avoid hand-twisted repairs; use proper connectors or replace the harness if multiple splices exist
  

• Use OEM-grade harnesses and connectors
  
• Avoid bypassing modules unless absolutely necessary
  
• Label and document all wiring repairs for future diagnostics
  
• Install a voltage monitor on the ECU power feed
  
• Secure harnesses with loom and clamps to prevent vibration damage
  
• Perform annual continuity checks on critical circuits
  

Purchasing used heavy machinery, such as excavators, skid steers, or loaders, can be a daunting process. Many buyers face challenges in finding reliable machines that can handle the rigors of tough job sites. When it comes to acquiring used equipment, several factors must be taken into account: condition, age, maintenance history, brand reputation, and the specific needs of the job.
The Struggles of Buying a Used Machine
The market for used heavy equipment is flooded with options, but finding the right machine can be overwhelming. As potential buyers, people often look for machines that have been well-maintained, are relatively new, and have a good track record of durability and performance. However, many machines are sold with hidden issues that may not become apparent until after purchase. These problems can include:

• Undisclosed damage: Whether it’s from a prior accident, poor handling, or lack of maintenance, these issues may not always be disclosed upfront.
  
• Wear and tear: Machines may have extensive wear on critical components, such as engines, hydraulic systems, or tracks, that can be expensive to repair.
  
• Lack of maintenance records: Without detailed maintenance records, it can be difficult to assess whether a machine has been serviced properly over the years.
  

• Age of the Equipment: The age of the machine is one of the first factors to consider. Older machines are likely to have more wear, but they can also be more affordable. On the other hand, newer machines might still have a lot of value left but come with a higher price tag. A balance between age, usage, and condition is key.
  
• Maintenance History: A well-maintained machine will often outperform an ill-maintained one, even if the ill-maintained machine is newer. Before purchasing, request maintenance records, check for repairs, and ensure that the machine has been serviced regularly by a professional.
  
• Hours of Operation: The number of hours a machine has been used is another critical indicator of its overall condition. Low-hour machines are often in better condition and have more life left in them, but they can also come at a premium price.
  
• Inspection of Key Components: Always inspect the most critical components of the machine, including:
  • Hydraulics: Look for any leaks or issues in the hydraulic lines, pumps, or cylinders.
    
  • Engine: Make sure the engine starts easily, runs smoothly, and doesn't produce excessive smoke.
    
  • Tracks and Tires: If you're buying a tracked machine, inspect the undercarriage and tracks for wear and any signs of damage. For wheeled equipment, check the tires for tread life and punctures.
    
• Brand Reputation: Certain manufacturers have earned reputations for producing more durable and reliable machines than others. Brands like Caterpillar, John Deere, and Komatsu have built strong reputations over decades. A trusted brand often ensures higher resale value and easier access to replacement parts.
  

• Condition of the Equipment: Both machines had visible wear on their tracks, signs of hydraulic leakage, and issues with engine performance.
  
• Pricing: The asking price for the John Deere 320D was higher than expected given its age, and it had been subjected to more wear than the CAT 262D.
  
• Lack of Documentation: Neither machine came with a clear history of maintenance or any recent service reports, making it difficult to assess their true condition.
  

1. Expand Your Search: Don’t limit yourself to local dealerships. Online marketplaces and auctions can often offer a wider range of options, though they require careful inspection and research.
   
2. Work with a Trusted Dealer: Building a relationship with a reputable equipment dealer can help ensure that you're getting a machine that has been properly inspected, serviced, and documented.
   
3. Get a Third-Party Inspection: If you're unsure about the condition of a machine, consider hiring an independent mechanic or inspector to examine the equipment. This can help identify potential issues before making a purchase.
   
4. Negotiate the Price: Don’t be afraid to negotiate the price based on the machine’s condition, potential repairs, or lack of service history. A fair price will reflect the current state of the equipment.
   
5. Look for Warranty or Service Plans: If possible, try to find a machine that still has a warranty or a service plan attached to it. Some dealers offer warranties for used equipment, which can provide peace of mind in case something goes wrong after the purchase.
   

The Development of SystemOne
Caterpillar introduced the SystemOne undercarriage in the early 2000s as a response to persistent wear and maintenance challenges in traditional track systems. Designed for medium-size track-type tractors such as the D3 through D6 series, SystemOne aimed to reduce operating costs, extend component life, and simplify service. It was developed at Caterpillar’s Peoria, Illinois facility and launched globally after extensive field testing in forestry, construction, and grading applications.
Unlike conventional undercarriages, which rely on rotating bushings and frequent pin turns, SystemOne uses sealed, non-rotating bushings and a center-tread idler design. This configuration distributes wear more evenly and eliminates the need for bushing turns—a common maintenance task that often requires specialized tools and downtime.
Core Features of SystemOne
SystemOne includes several integrated components:

• Non-rotating bushings: Designed to wear evenly without turning, reducing internal stress and eliminating turn procedures.
  
• Center-tread idlers: Align with the track centerline to reduce scalloping and improve alignment.
  
• Lifetime-sealed cartridges: Pins and bushings are sealed for life, minimizing contamination and grease loss.
  
• Resilient track rollers: Designed to flex under load and absorb shock, reducing flange wear.
  
• Single-piece track links: Forged for strength and designed to maintain pitch over time.
  

• Accelerated wear on bushings in high-abrasion environments
  
• Uneven wear on idler flanges when operating on slopes or in side-cutting applications
  
• Track elongation due to link wear, despite sealed cartridges
  
• Roller shell thinning in rocky terrain
  

• Maintain proper track tension—neither too tight nor slack. Over-tension accelerates roller and bushing wear.
  
• Inspect roller flanges and idler alignment every 500 hours
  
• Use wide shoes in soft ground to reduce bushing pressure
  
• Avoid prolonged reverse travel, which stresses bushings unevenly
  
• Clean undercarriage daily in muddy or abrasive conditions
  
• Monitor track pitch and link height with calipers or wear gauges
  

• No bushing turns required
  
• Lower maintenance intervals
  
• Improved ride quality due to resilient rollers
  
• Better alignment and reduced scalloping
  
• Simplified service procedures
  

The Evolution of the CAT 973 Series
The Caterpillar 973 track loader was introduced in the late 1980s as part of Caterpillar’s push to modernize its crawler loader lineup. Built on the success of the 955 and 977 series, the 973 offered increased horsepower, hydrostatic drive, and improved operator ergonomics. With an operating weight of over 50,000 lbs and a bucket capacity exceeding 4 cubic yards, the 973 became a staple in demolition, land clearing, and heavy excavation.
By the early 2000s, the 973 had evolved into the 973C and later the 973D, incorporating electronic controls and emissions-compliant engines. However, the original 973—especially pre-electronic models like the 86G prefix—remains widely used due to its mechanical simplicity and field serviceability.
Symptoms of Steering Malfunction
Operators encountering steering issues on the 973 often report:

• Delayed response when pressing the right or left steering pedal
  
• Complete loss of steering on one side
  
• Machine reversing instead of turning when engaging a pedal
  
• Inconsistent behavior after several hours of operation
  
• Increased engine load or bogging during attempted turns
  

• Dual variable displacement pumps
  
• Track drive motors with case drain and shift ports
  
• Brake lines and pressure regulators
  
• Mechanical or electronic control linkages
  

• Each track motor has a case drain port to relieve internal pressure
  
• If blocked, pressure builds and prevents motor rotation
  
• Spec: Case drain pressure should be 0–2 psi during testing
  

• Capping the brake line is sometimes used to lock brakes during diagnostics
  
• On the 973, this can cause the machine to move unexpectedly when placed in gear
  
• Caution: Always test with transmission lever fully back and brakes engaged
  

• Two taps on each motor: one for shifting, one for case drain
  
• Using the wrong port during testing can yield false results
  
• Correct tap: The one closer to the center of the machine
  

• Holding the transmission at stall for more than 30 seconds can damage port plates
  
• Always allow 30 seconds in neutral between stall tests
  

• Dirty or degraded fluid can cause valve sticking and pump inefficiency
  
• Recommended fluid: Caterpillar HYDO Advanced 10 or equivalent
  
• Change interval: Every 1,000 hours or annually
  

• Mechanical linkages under the seat armrest may wear or misalign
  
• Check for three switches under the right-hand armrest—some models use them for control logic
  

• Cap the brake line carefully and engage the transmission in gear
  
• Locate the case drain tap and connect a pressure gauge
  
• Pull the transmission lever fully back and observe pressure
  
• If pressure exceeds 2 psi, the motor may be internally leaking or blocked
  
• Inspect fluid condition and check for metal particles
  
• Test both motors independently to compare response
  

• Change hydraulic filters every 500 hours
  
• Inspect control linkages quarterly
  
• Test case drain pressure annually
  
• Avoid prolonged stall testing
  
• Use OEM-grade fluid and monitor for contamination
  
• Keep a service log with fault codes and pressure readings
  

• Operation & Maintenance Manual: SEBU5848
  
• Parts Manual: SEBP1387