Caterpillar 955 and 977: A Detailed Overview and Comparison

[MikePhua]

Caterpillar has long been known for producing robust, reliable construction machinery, and the 955 and 977 series of track loaders are no exception. These machines have earned a reputation for their versatility in various industries, from construction and mining to forestry and agriculture. However, as older models, potential buyers and operators often have questions regarding their performance, maintenance, and the best ways to handle common issues.
This article will explore the history, specifications, and key differences between the CAT 955 and 977 track loaders, addressing frequently asked questions and providing practical tips for operating and maintaining these machines.
Caterpillar 955: A Classic Track Loader
Introduced in the early 1950s, the Caterpillar 955 track loader was one of the company’s pioneering models in the compact track loader category. This model quickly became popular due to its versatility and ability to handle a wide range of tasks, including loading, digging, and lifting. The 955 was equipped with a diesel engine and a hydraulic system, providing the power needed for both heavy-duty tasks and fine precision work.
The CAT 955 became a cornerstone of many construction fleets and remained in production for several decades. Although it has since been discontinued, it continues to be a valuable machine in many industries, especially in the form of used equipment that can still provide reliable service if maintained properly.
CAT 955 Key Specifications

• Engine Power: 95 horsepower (71 kW)
  
• Operating Weight: Approximately 16,000 lbs (7,257 kg)
  
• Bucket Capacity: 1.0 - 1.5 cubic yards (0.76 - 1.15 cubic meters)
  
• Lift Capacity: 5,000 - 6,000 lbs (2,268 - 2,722 kg)
  
• Hydraulic Flow: 22 gallons per minute (83 liters per minute)
  
• Transmission: 4-speed mechanical transmission
  

The 955's simple design and relatively low maintenance costs have contributed to its long-lasting presence in the market. Though its horsepower may seem modest by today’s standards, it was more than sufficient for the tasks it was designed for in the mid-20th century.
Advantages of the CAT 955

1. Durability: The 955 was built to last, and many of these machines are still in operation today, with the right care and maintenance.
   
2. Versatility: With a variety of attachments, including buckets, forks, and rippers, the 955 could be adapted to numerous tasks on the job site.
   
3. Simplicity: Compared to modern loaders, the 955's mechanical design made it easier to repair and maintain, especially for operators with basic mechanical knowledge.
   

Common Issues and Maintenance Tips for the CAT 955

1. Hydraulic System Leaks: One of the most common issues with older machines like the 955 is hydraulic fluid leakage, often caused by worn seals or hose degradation. Regularly inspect the hydraulic lines and components to catch leaks early.
   
2. Engine Overheating: The 955's cooling system can become clogged or inefficient over time. Periodic cleaning of the radiator and ensuring the cooling system is free of debris is essential to preventing overheating.
   
3. Transmission Issues: The 955's mechanical transmission can experience wear in the clutch or transmission fluid lines, leading to shifting problems. Regular transmission fluid checks and adjustments are necessary.
   

Caterpillar 977: An Upgrade with More Power
Released in the 1960s, the Caterpillar 977 series of track loaders represented an upgrade over the 955, with more horsepower, better lifting capacity, and improved hydraulics. The 977 series was designed to handle larger loads and more demanding tasks, making it ideal for heavy-duty operations such as road construction, mining, and large-scale material handling.
The 977 came with enhanced features that allowed for improved performance in rough terrain. It also featured more advanced hydraulics, allowing for smoother and more precise control of the loader arms and bucket.
CAT 977 Key Specifications

• Engine Power: 110 horsepower (82 kW)
  
• Operating Weight: Approximately 21,000 lbs (9,525 kg)
  
• Bucket Capacity: 1.5 - 2.0 cubic yards (1.15 - 1.53 cubic meters)
  
• Lift Capacity: 6,000 - 8,000 lbs (2,722 - 3,629 kg)
  
• Hydraulic Flow: 25 gallons per minute (95 liters per minute)
  
• Transmission: 4-speed hydraulic powershift transmission
  

The 977 was aimed at larger-scale operations, offering increased power and capacity to handle more demanding tasks. It was also equipped with a more comfortable operator cabin, providing better ergonomics and visibility.
Advantages of the CAT 977

1. Greater Power and Capacity: With a more powerful engine and increased lift capacity, the 977 can handle larger loads and more intense job site conditions.
   
2. Advanced Hydraulics: The 977’s improved hydraulic system provides better lifting power and more controlled movement of the loader’s arms and attachments.
   
3. Enhanced Comfort and Operator Visibility: The 977’s cabin was designed for greater operator comfort, with improved visibility, a better seat, and more intuitive controls.
   

Common Issues and Maintenance Tips for the CAT 977

1. Hydraulic Pump Wear: The hydraulic pump is often subject to wear, especially in older models. Check the hydraulic fluid for contamination and inspect the pump for any signs of failure.
   
2. Final Drive Maintenance: The 977's final drive system, which transfers power to the tracks, can be prone to wear. Regularly inspect the final drive gears and bearings for damage and lubricate as needed.
   
3. Undercarriage Wear: The undercarriage, including tracks, rollers, and sprockets, can wear out over time, especially if the machine operates in harsh conditions. Regularly inspect the undercarriage for signs of excessive wear and replace components as needed.
   

Key Differences Between the CAT 955 and 977
While both the CAT 955 and 977 are track loaders from Caterpillar, they differ in several important aspects:

1. Engine Power: The 977 has more horsepower (110 hp) compared to the 955 (95 hp), allowing for better performance in demanding tasks.
   
2. Lift Capacity: The 977 has a higher lifting capacity, making it more suited for heavy-duty operations. It can lift up to 8,000 lbs, while the 955 is limited to around 6,000 lbs.
   
3. Bucket Capacity: The 977 also has a larger bucket capacity (1.5 to 2.0 cubic yards) compared to the 955’s 1.0 to 1.5 cubic yards, enabling it to handle larger volumes of material.
   
4. Size and Weight: The 977 is considerably heavier than the 955, which means it can handle larger loads but may have slightly less maneuverability in tight spaces.
   

Conclusion: Choosing Between the CAT 955 and 977
Both the CAT 955 and 977 track loaders have proven themselves as durable and capable machines in various industries. The 955 is a great option for smaller, less demanding tasks and offers simplicity in maintenance and operation. On the other hand, the 977 is better suited for larger, more complex jobs where additional power, capacity, and advanced hydraulics are required.
For those working with heavier materials or in more challenging environments, the CAT 977 offers clear advantages in terms of power and lifting ability. However, for businesses or operators on a budget or dealing with lighter tasks, the CAT 955 remains a highly functional and cost-effective choice, especially when well-maintained.
When selecting a used machine, it’s crucial to consider the condition of key components such as the engine, hydraulics, and undercarriage. Both models are relatively old and may require more frequent maintenance and repair, but with the right care, they can continue to serve well on job sites for years to come.