Introduction to the Bush Hog 278 Gearbox
The Bush Hog 278 is a widely used rotary cutter, known for its durability and efficiency in tackling tough mowing jobs in agriculture, construction, and land management. It is especially popular for clearing brush, thick grass, and even small trees. The gearbox is a critical component of this machine, transferring power from the engine to the blade assembly, ensuring efficient operation. However, like many pieces of heavy equipment, the Bush Hog 278 gearbox can face issues that need addressing to ensure smooth operation.
In this article, we will discuss common problems associated with the Bush Hog 278 gearbox, explore the causes behind them, and provide solutions based on real-world experiences and industry practices.
Common Problems with the Bush Hog 278 Gearbox

• Overheating: One of the most common issues that users report is overheating of the gearbox. This can occur due to several factors, such as insufficient lubrication, excessive load on the cutter, or lack of proper maintenance. Overheating can cause significant damage to the internal components, leading to costly repairs or replacements.
  
• Oil Leaks: Gearboxes are designed to be sealed units that retain oil for proper lubrication. However, over time, seals may wear out, leading to oil leaks. This issue is not only inconvenient but can also result in the gearbox running dry, which causes excessive wear and potential failure of the gearbox.
  
• Gear Wear and Damage: Gearboxes rely on precise gearing mechanisms to transfer power. If these gears are not properly lubricated or are exposed to excessive stress, they can wear down or break. This can lead to grinding noises, difficulty in operation, or a complete failure of the gearbox.
  
• Failure of Bearings: Bearings are essential for the smooth rotation of the gears within the gearbox. If these bearings fail, it can lead to metal-on-metal contact, creating friction, heat, and ultimately, gearbox failure. Bearing failure is often a result of prolonged use without proper maintenance or the use of low-quality lubricants.
  

• Inadequate Lubrication: The gearbox relies heavily on lubrication to reduce friction and ensure smooth operation. If the oil level is too low or the oil becomes contaminated, it can cause the gears to grind, overheat, and eventually fail. It’s important to regularly check the oil levels and replace it as needed.
  
• Improper Usage: Operating the Bush Hog 278 under conditions that exceed its recommended load capacity can put excessive strain on the gearbox. This can lead to overheating, gear wear, and failure of internal components. Always follow the manufacturer’s guidelines for optimal operation.
  
• Neglecting Maintenance: Regular maintenance is essential for keeping the gearbox running smoothly. Failing to clean and lubricate the gearbox regularly can lead to the buildup of debris, which can damage gears and bearings. In addition, neglecting to inspect the gearbox for potential issues can allow small problems to develop into major ones.
  
• Environmental Factors: Exposure to extreme temperatures, dirt, and moisture can also contribute to gearbox problems. In areas where the equipment is exposed to high humidity or dusty conditions, the seals can degrade faster, and the oil may become contaminated more quickly.
  

• Regular Lubrication and Oil Changes: Ensure that the gearbox is always properly lubricated. Regularly check the oil levels and replace the oil according to the manufacturer’s schedule. It’s also important to use the recommended oil type, as using the wrong oil can lead to premature wear.
  
• Proper Usage and Load Management: Always follow the manufacturer’s guidelines regarding load capacities and operating conditions. Overloading the cutter or running it at high speeds for prolonged periods can put unnecessary strain on the gearbox.
  
• Routine Inspection and Maintenance: Set up a routine maintenance schedule that includes inspecting the gearbox for signs of wear, checking oil levels, and cleaning out any debris that may have accumulated. Catching issues early can prevent larger problems down the road.
  
• Seal and Bearing Replacement: If oil leaks are detected, replace the seals immediately to prevent further damage. Bearings should also be checked regularly for signs of wear or damage. Replacing these components early can save you from having to replace the entire gearbox.
  
• Environmental Considerations: When operating in dusty or wet conditions, it’s important to clean the gearbox more frequently. Protecting the machine from environmental factors such as water and excessive dirt can help preserve the seals and prevent contamination.
  

The CAT 420E backhoe loader is one of the most popular models in the Caterpillar lineup. Known for its impressive performance, versatility, and durability, it serves as an essential tool for various construction, landscaping, and agriculture tasks. In this article, we explore the specifications, capabilities, and unique features of the CAT 420E, along with insights into its development and usage in real-world applications.
Development History and Background
Caterpillar has a long legacy in manufacturing construction equipment, with the 420E being a part of their backhoe loader series. The 420E was designed to replace its predecessor, the 420D, offering enhanced engine performance, better hydraulic power, and improved operator comfort. The 420E is a part of Caterpillar’s “E-Series” family, which represents a transition to more efficient and environmentally-friendly machinery.
Caterpillar, founded in 1925, is one of the world's largest manufacturers of construction and mining equipment. The company is known for its continuous innovation and focus on durability, which is why Caterpillar machines are widely respected and sought after in industries worldwide.
CAT 420E Specifications
The CAT 420E backhoe loader comes equipped with a range of features that make it a standout in its class:

• Engine:
  • Model: C4.4 ACERT
    
  • Rated Power: 92 kW (123 hp)
    
  • Displacement: 4.4 L
    
  • Type: Turbocharged diesel engine (Caterpillar ACERT technology ensures better fuel efficiency and compliance with emission standards)
    
• Dimensions:
  • Operating Weight: 7,850 kg (17,300 lbs)
    
  • Length: 5,850 mm (231.9 in)
    
  • Width: 2,350 mm (92.5 in)
    
  • Height: 3,720 mm (146.5 in)
    
• Hydraulic System:
  • Maximum Flow: 143 L/min
    
  • Digging Force (Backhoe): 6,730 kg (14,830 lbs)
    
  • Digging Force (Loader): 5,640 kg (12,450 lbs)
    
• Performance:
  • Maximum Digging Depth (Backhoe): 5,810 mm (228 in)
    
  • Loader Bucket Capacity: 1.0 m³ (1.3 yd³)
    
• Transmission:
  • Type: Hydrostatic drive
    
  • Speeds: 4 Forward, 4 Reverse gears
    
  • Maximum Speed: 40 km/h (24.8 mph)
    
• Fuel Capacity:
  • 140 L (37 gal), ensuring extended operating hours for large projects.
    

1. Advanced Hydraulic System:
   The hydraulic system on the 420E delivers more power to the backhoe, allowing for faster cycle times and improved lifting capacity. With a maximum flow of 143 L/min, it ensures smooth and efficient operation, even when working with heavy loads.
   
2. Comfort and Productivity:
   The operator's cab of the 420E is designed for comfort. The seating is ergonomically designed with easy access to controls, minimizing operator fatigue during long working hours. The cab is also fully sealed to reduce noise levels and vibration, providing a quieter and more pleasant work environment.
   
3. Fuel Efficiency:
   Powered by the C4.4 ACERT engine, the 420E offers significant fuel savings compared to previous models. The engine complies with stringent Tier 3 emissions standards while delivering consistent power, making it an eco-friendly option for construction projects.
   
4. Versatility:
   As a backhoe loader, the 420E is capable of performing multiple tasks with just one machine. The loader bucket can be used for lifting, leveling, and digging, while the backhoe arm allows for deep trenching and digging in narrow spaces. This makes it a cost-effective solution for both small and large-scale construction projects.
   

                           

ID：1826544

• Brand: Komatsu
  
• Model: PC270-7
  
• Year of Manufacture: 2012
  
• Hours Worked: 13,500 hours
  
• Location: Pingdingshan City, Henan Province
  

• Brand: Komatsu
  
• Model: PC270-7
  
• Year of Manufacture: 2012
  
• Hours: 13,500 hours
  
• Location: Pingdingshan, Henan, China
  
• Operating Weight: 27,460 kg
  
• Bucket Capacity: 1.3 m³
  

• Maximum Digging Radius: 10,100 mm
  
• Maximum Digging Depth: 6,460 mm
  
• Maximum Digging Height: 10,000 mm
  
• Maximum Dumping Height: 7,035 mm
  
• Vertical Digging Depth: 5,650 mm
  

• Fuel Tank Capacity: 400L
  
• Hydraulic Oil Capacity: 143L
  
• Engine Oil Capacity: 24L
  
• Coolant Capacity: 30.9L
  

1. Road Construction: With its powerful engine and robust hydraulic system, it can clear land, excavate trenches, and move large amounts of material.
   
2. Mining Operations: The PC270-7 excels in mining tasks, where it needs to extract materials from tough soil or rock.
   
3. Landscaping and Demolition: Its long reach and precise control make it effective in landscaping and demolition projects.
   
4. General Construction: Whether it’s for site preparation or general excavation, the PC270-7 offers the flexibility needed for numerous projects.
   

                               

ID：1826540

• Brand: Caterpillar
  
• Model: CAT®313D2 GC Small Hydraulic
  
• Year of Manufacture: 2018
  
• Hours Worked: 6,100 hours
  
• Location: Hechi City, Guangxi Province
  

• Weight and Size:
  • Total Operating Weight: 12,500 kg
    
  • Bucket Capacity: 0.53 m³
    
  • Boom Length: 4650 mm
    
  • Arm Length: 2500 mm
    
  • Transport Dimensions:
    • Total Length: 7610 mm
      
    • Total Width: 2760 mm
      
    • Total Height: 2830 mm
      
• Power System:
  • Engine Model: Cat C4.4
    
  • Rated Power: 74.5 kW
    
  • Engine Displacement: 4.4 L
    
  • Cooling Type: Water Cooled
    
  • Cylinder Bore x Stroke: 105 x 127 mm
    
  • Maximum Torque: 30.9 Nm
    
• Performance and Hydraulic System:
  • Maximum Digging Depth: 5540 mm
    
  • Maximum Digging Height: 8490 mm
    
  • Maximum Vertical Digging Depth: 4610 mm
    
  • Maximum Dumping Height: 6100 mm
    
  • Swing Speed: 11.2 rpm
    
  • Maximum Traction Force: 114 kN
    
  • Walking Speed: 5.1 km/h
    

                               

ID：1826538

• Brand: Komatsu
  
• Model: PC130-7
  
• Year of Manufacture: 2014
  
• Hours Worked: 1,020 hours
  
• Location: Shaoguan City, Guangdong Province
  

• Brand: Komatsu
  
• Model: PC130-7
  
• Year of Manufacture: 2014
  
• Operating Hours: 1020 hours
  
• Location: Shaoguan City, Guangdong
  
• Operating Weight: 12,600 kg
  
• Bucket Capacity: 0.53 m³
  
• Arm Length: 2100 mm
  
• Engine Type: Diesel, Turbocharged, Water-cooled
  
• Engine Model: Komatsu SAA4D95LE-3
  
• Power Output: 66 kW at 2200 rpm
  
• Displacement: 3.26 L
  
• Hydraulic System: The main pump flow rate is 226 L/min.
  

• Ground Pressure: 38 kPa
  
• Swing Speed: 11 rpm
  
• Climbing Capacity: 70% or 30°
  
• Bucket Digging Force: 93.2 kN
  
• Arm Digging Force: 61.8 kN
  
• Travel Speed: 2.7–5.5 km/h
  

• Fuel Tank: 247 L
  
• Hydraulic Tank: 90 L
  
• Engine Oil Capacity: 11 L
  
• Cooling Fluid: 13.4 L
  

• Transport Length: 7599 mm
  
• Transport Height: 2175 mm
  
• Cab Height: 2175 mm
  
• Ground Clearance: 400 mm
  
• Rear Swing Radius: 2110 mm
  
• Track Length: 3610 mm
  
• Track Gauge: 1990 mm
  
• Track Width: 500 mm
  

                               

ID：1826537

• Brand: Hyundai
  
• Model: R215VS
  
• Year of Manufacture: 2020
  
• Hours Worked: 5,900 hours
  
• Location: Nanyang City, Henan Province
  

• Maximum Digging Radius: 9,930 mm
  
• Maximum Digging Depth: 6,800 mm
  
• Maximum Digging Height: 9,730 mm
  
• Maximum Vertical Digging Depth: 6,060 mm
  
• Maximum Lifting Height: 6,910 mm
  

                                       

ID：1826535

• Brand: Hitachi
  
• Model: ZX60
  
• Year of Manufacture: 2012
  
• Hours Worked: 9,500 hours
  
• Location: Yiyang City, Hunan Province
  

• Brand: Hitachi
  
• Model: ZX60
  
• Year: 2012
  
• Operating Hours: 9,500 hours
  
• Location: Yiyang, Hunan Province, China
  

• Weight: 5,850 kg
  
• Bucket Capacity: 0.22 m³
  
• Arm Length: 3.49 m
  
• Boom Length: 1.6 m (Reinforced Version)
  
• Engine Model: Isuzu CC-4JG1
  
• Engine Power: 40.5 kW at 2100 rpm
  
• Cooling Method: Water-cooled
  
• Cylinder Count: 4 cylinders
  
• Displacement: 3.059 L
  
• Operating Mode: Direct injection
  
• Ground Pressure: 33 kPa
  
• Swing Speed: 9.3 rpm
  
• Climbing Ability: 70% / 35°
  
• Bucket Digging Force: 41.4 kN
  
• Arm Digging Force: 28.4 kN
  
• Walking Speed: 2.5 km/h (low) / 4.5 km/h (high)
  

• Main Pump Maximum Flow: 2x variable displacement piston pumps, 2x gear pumps
  
• Hydraulic Motor Type: Axial piston motor (for rotation), variable displacement axial piston motors (for walking)
  
• Main Relief Pressure: 24.5 MPa
  
• Hydraulic Oil Capacity: 61 L (95 L max)
  

• Fuel Tank: 120 L
  
• Engine Oil Capacity: 12 L
  
• Hydraulic Oil Capacity: 61 L (full capacity is 95 L)
  
• Coolant Capacity: 8 L
  

• Total Transport Length: 6,060 mm
  
• Width: 2,060 mm
  
• Height: 2,470 mm
  
• Cab Height: 2,470 mm
  
• Ground Clearance: 620 mm
  
• Minimum Ground Clearance: 310 mm
  
• Swing Radius (front): 2,510 mm
  
• Rear Swing Radius: 1,650 mm
  
• Track Length: 2,480 mm
  
• Track Gauge: 1,600 mm
  
• Track Pad Width: 400 mm
  
• Total Track Width: 2,000 mm
  
• Ground Contact Length: 2,000 mm
  

• Maximum Digging Radius: 6,250 mm
  
• Maximum Digging Depth: 3,850 mm
  
• Maximum Digging Height: 5,800 mm
  
• Maximum Dumping Height: 4,080 mm
  
• Maximum Vertical Digging Depth: 3,300 mm
  
• Blade Lift/Push Depth: 430 mm / 400 mm
  

                                       

ID：1826529

• Brand: Caterpillar
  
• Model: 320C
  
• Year of Manufacture: 2003
  
• Hours Worked: 13,000 hours
  
• Location: Yulin City, Guangxi Province
  

• Brand: Caterpillar
  
• Model: 320C
  
• Year of Manufacture: 2003
  
• Operating Hours: 13,000 hours
  
• Location: Guangxi, Yulin City, China
  
• Operating Weight: 21,115 kg
  
• Bucket Capacity: 0.8 m³
  
• Boom Length: 5,680 mm
  
• Stick Length: 2,900 mm
  
• Power System: Conventional power
  
• Bucket Type: Backhoe
  

• Engine Model: Caterpillar CAT 3066 ATAAC
  
• Rated Power: 110 kW at 1,800 rpm
  
• Displacement: 6.4 L
  
• Cylinder Bore × Stroke: 102 × 130 mm
  
• Cooling System: Water-cooled
  

• Ground Pressure: 48.02 kPa
  
• Rotation Speed: 11.5 rpm
  
• Bucket Digging Force: 132 kN
  
• Stick Digging Force: 99 kN
  
• Travel Speed: 5.5 km/h
  

• Main Pump Maximum Flow Rate: 205 L/min
  
• Travel Hydraulic Circuit Pressure: 34.4 MPa
  
• Rotation Hydraulic Circuit Pressure: 26 MPa
  
• Working Hydraulic Circuit Pressure: 34.3 MPa
  
• Pilot Circuit Pressure: 4.12 MPa
  
• Bucket Cylinder: 1 × 120 × 1,030 mm
  
• Stick Cylinder: 1 × 140 × 1,430 mm
  
• Boom Cylinder: 2 × 120 × 1,260 mm
  

• Fuel Tank Capacity: 320 L
  
• Hydraulic Tank Capacity: 120 L
  
• Engine Oil Change Capacity: 30 L
  
• Coolant Capacity: 24 L
  
• Hydraulic System Capacity: 200 L
  

• Transport Length: 9,390 mm
  
• Transport Width: 2,800 mm
  
• Transport Height: 3,050 mm
  
• Cab Height: 3,050 mm
  
• Minimum Ground Clearance: 460 mm
  
• Rear Swing Radius: 2,770 mm
  
• Track Length: 4,070 mm
  
• Track Gauge: 2,200 mm
  
• Track Shoe Width: 600 mm
  
• Track Ground Length: 3,260 mm
  

• Maximum Digging Depth: 6,550 mm
  
• Maximum Digging Height: 9,440 mm
  
• Maximum Dumping Height: 6,770 mm
  
• Maximum Vertical Digging Depth: 5,440 mm
  
• Maximum Working Radius: 9,710 mm
  

                           

ID：1826521

• Brand: Caterpillar
  
• Model: 336D2 Hydraulic
  
• Year of Manufacture: 2017
  
• Hours Worked: 17,943 hours
  
• Location: Tai'an City, Shandong Province
  

• Machine Specifications:
  • Weight: 34,600 kg
    
  • Bucket Capacity: 1.88 m³
    
  • Arm Length: 6,500 mm
    
  • Stick Length: 2,800 mm
    
  • Engine Model: Caterpillar C9 ACERT
    
  • Power Output: 208 kW at 2,000 RPM
    
  • Engine Displacement: 8.8 liters
    

• Rotary Speed: 8.3 RPM
  
• Climbing Ability: 70% (35° slope)
  
• Maximum Traction Force: 300 kN
  
• Travel Speed: 4.6 km/h
  
• Swing Torque: 109 Nm
  

• Main Pump Flow: 281 l/min
  
• Pilot Pump Flow: 40 l/min
  
• Hydraulic System Pressure: 35 MPa
  
• Swing Motor Type: Axial Piston Motor
  
• Travel Motor Type: Variable Displacement Axial Piston Motor
  

• Fuel Tank Capacity: 620 liters
  
• Hydraulic Oil Capacity: 175 liters
  
• Engine Oil Capacity: 41 liters
  
• Coolant Capacity: 40 liters
  
• Hydraulic System Capacity: 410 liters
  

• Total Transport Length: 11,210 mm
  
• Width: 3,190 mm
  
• Height: 3,670 mm
  
• Cab Height: 3,140 mm
  
• Ground Clearance: 510 mm
  
• Track Length: 4,590 mm
  
• Track Gauge: 2,590 mm
  

• Maximum Digging Depth: 8,210 mm
  
• Maximum Digging Height: 10,730 mm
  
• Maximum Dump Height: 7,510 mm
  
• Maximum Vertical Digging Depth: 6,290 mm
  
• Maximum Digging Radius: 11,760 mm
  

                               

ID：1826254

• Brand: Doosan
  
• Model: DH225-9
  
• Year of Manufacture: 2011
  
• Hours Worked: 10,800 hours
  
• Location: Harbin City, Heilongjiang Province
  

• Brand: Doosan
  
• Model: DH225-9
  
• Year of Manufacture: 2011
  
• Hours of Operation: 10,800 hours
  
• Location: Harbin, Heilongjiang, China
  

• Operating Weight: 22 tons
  
• Power Type: Traditional power
  
• Manufacturer: Joint venture/import
  
• Bucket Type: Backhoe bucket
  

• Bucket Capacity: The backhoe bucket is designed to deliver solid performance with a strong digging force, suitable for a variety of tasks such as trenching, excavation, and loading.
  
• Hydraulic System: The hydraulic system of the DH225-9 is built to maximize efficiency, allowing for faster response times and superior fuel efficiency. The variable displacement pumps contribute to optimized fuel consumption during operation, which is particularly valuable for long-duration projects.
  
• Engine Power: The Doosan DH225-9 is equipped with a highly reliable engine that provides robust power while maintaining fuel efficiency.
  

• Durability: Doosan machines are well-known for their resilience in harsh environments, and the DH225-9 is no different. It stands up well to rugged conditions, offering operators a reliable workhorse that performs consistently.
  
• Maintenance: The design of the DH225-9 includes features that make it easier to maintain, which translates to reduced downtime and more productive hours. Simple and accessible components contribute to faster repairs and easier part replacements.