Replacing Drive Chains on the Case 1845C Skid Steer the Right Way

[MikePhua]

The Case 1845C and Its Chain-Driven Legacy
The Case 1845C Uni-Loader was introduced in the late 1980s and remained in production until the early 2000s, becoming one of the most successful skid steer models ever built. With over 60,000 units sold, it earned a reputation for simplicity, durability, and ease of service. Powered by a 60-horsepower Cummins 4B diesel engine and featuring a mechanical chain-drive system, the 1845C was designed to thrive in harsh environments with minimal electronics and maximum mechanical reliability.
Unlike modern hydrostatic drive systems, the 1845C uses dual drive chains to transfer power from the hydraulic motors to the wheels. This setup allows for robust torque delivery and straightforward maintenance, but it also requires periodic inspection and replacement—especially in high-hour machines or those used in abrasive conditions.
Terminology Notes

• Drive Chain: A roller chain that transmits torque from the hydraulic motor to the axle sprockets
  
• Sprocket: A toothed wheel that engages the chain and rotates the axle
  
• Chain Case: The enclosed compartment housing the drive chains and sprockets
  
• Tensioner: A mechanical or spring-loaded device that maintains proper chain tension
  
• Final Drive: The last stage in the drivetrain before power reaches the wheels
  

Symptoms of Worn or Failed Drive Chains
Operators may notice several signs when drive chains are due for replacement:

• Clunking or popping noises during travel
  
• Uneven or jerky movement, especially when turning
  
• Chain slap or excessive play in the chain case
  
• Visible wear or elongation when inspected
  
• Leaking chain case oil due to seal damage from vibration
  

In 2014, a contractor in Ohio reported that his 1845C began pulling to one side under load. After opening the chain case, he found the left-side drive chain had stretched beyond spec and was skipping teeth on the sprocket. Replacing both chains restored balanced movement and eliminated the noise.
Preparation and Safety Before Replacement
Before beginning the replacement process:

• Park the machine on level ground and block the wheels
  
• Disconnect the battery to prevent accidental startup
  
• Remove the rear wheels and chain case covers
  
• Drain the chain case oil into a clean container for inspection
  
• Clean the area thoroughly to avoid contamination during reassembly
  

Use proper lifting equipment to support the loader arms if they need to be raised. Always wear gloves and eye protection when working around chains and sprockets.
Step-by-Step Chain Replacement Procedure

• Remove the old chain by loosening the tensioner and disengaging it from the sprockets
  
• Inspect sprockets for wear—replace if teeth are hooked or uneven
  
• Clean the chain case and inspect for cracks or seal damage
  
• Install the new chain, ensuring it seats properly on both sprockets
  
• Adjust tension using the tensioner mechanism—there should be minimal slack but no binding
  
• Refill the chain case with fresh gear oil (typically SAE 90 or manufacturer-recommended equivalent)
  
• Reinstall covers and wheels, torque bolts to spec
  
• Test drive the machine slowly to verify smooth operation
  

Some operators prefer to replace both chains simultaneously to maintain balance and avoid future downtime. Always use matched chains from reputable suppliers to ensure consistent pitch and strength.
Preventative Maintenance and Inspection Tips
To extend chain life and avoid premature failure:

• Check chain tension monthly
  
• Inspect oil level and condition in the chain case every 100 hours
  
• Replace chain case oil every 500 hours or annually
  
• Avoid aggressive turning on hard surfaces that stress the chains
  
• Listen for unusual noises during operation and investigate promptly
  

For machines operating in sandy or wet conditions, consider more frequent inspections and oil changes. Contaminants can accelerate chain wear and damage seals.
Modern Comparisons and Design Evolution
While the 1845C uses mechanical chain drives, newer Case models like the SV280 and TV370 feature hydrostatic drive systems with electronically controlled motors. These systems offer smoother control and reduced maintenance but are more complex and costly to repair.
The 1845C remains popular among independent contractors and rental fleets due to its mechanical simplicity and low operating costs. Many units have surpassed 10,000 hours with original drive components thanks to regular maintenance and careful operation.
Conclusion
Replacing drive chains on the Case 1845C is a manageable task that restores performance and prevents costly drivetrain damage. With the right tools, clean procedures, and attention to detail, operators can keep their machines running strong for years. In the world of compact loaders, the 1845C proves that simple engineering—when cared for properly—can outlast the trends and keep working long after others retire.