Coupling Chain Replacement for the John Deere 170 Skid Steer

[MikePhua]

The John Deere 170 and Its Mechanical Simplicity
The John Deere 170 skid steer was part of Deere’s early compact equipment lineup, introduced during the late 1980s to meet growing demand for maneuverable, jobsite-friendly loaders. Built with a focus on mechanical reliability and ease of maintenance, the 170 featured a chain-driven transmission system, hydraulic lift arms, and a compact frame suited for landscaping, agriculture, and light construction. Though production numbers were modest compared to later models like the 240 and 318, the 170 earned a loyal following among operators who valued its straightforward design and rugged build.
At the heart of its drive system lies a coupling chain that links the engine’s output to the hydraulic pump or transmission input. This chain is essential for transferring torque and maintaining synchronized movement between components. When missing or damaged, the machine becomes inoperable, and sourcing the correct replacement becomes a priority.
Identifying the Correct Coupling Chain
For the John Deere 170, the coupling chain specification is:

• Chain Type: No. 50-2 (double strand)
  
• Link Count: 16 links
  
• Assembly Components: AH66615 and AP15292
  

This configuration is relatively common in industrial applications, making it easier to source replacements from aftermarket suppliers or online platforms. However, it’s critical to match both the pitch and the width of the chain to the original sprocket, which in this case is a 16-tooth unit. Using a mismatched chain can lead to premature wear, misalignment, or even catastrophic failure under load.
Terminology Clarification

• No. 50-2 Chain: A double-strand roller chain with a pitch of 0.625 inches, commonly used in power transmission
  
• Link: The individual segment of a chain, consisting of inner and outer plates, rollers, and pins
  
• Sprocket: A toothed wheel that engages with the chain to transmit motion
  
• Coupling: A mechanical connection between two rotating shafts or components
  

Installation Tips and Precautions
Before installing a new coupling chain, it’s essential to inspect the sprocket teeth for wear or damage. Worn sprockets can accelerate chain degradation and reduce efficiency. Additionally, the shaft should be rotated manually to ensure it moves freely—if it’s locked up, the original chain may have been removed due to internal binding or mechanical failure.
Steps for installation:

• Clean sprocket and shaft surfaces thoroughly
  
• Align both sprockets to ensure parallel rotation
  
• Install the chain with proper tension—neither too tight nor too loose
  
• Use a master link with a secure clip or rivet
  
• Rotate the system manually to confirm smooth operation before starting the engine
  

If the shaft resists movement, further inspection is needed. Binding may result from seized bearings, hydraulic lock, or internal gear damage. In such cases, forcing the chain into place can worsen the issue.
Field Anecdotes and Lessons Learned
A technician in Texas acquired a used John Deere 170 only to discover the coupling chain was missing. After sourcing a compatible chain online, he installed it but noticed resistance when turning the shaft. Upon further inspection, he found debris lodged in the pump housing, which had caused the original chain to snap. Clearing the obstruction restored full function, and the machine returned to service.
Another operator in Alberta shared that his 170 had gone through three chains in two years due to misaligned sprockets. After fabricating a custom shim to correct the angle, chain life improved dramatically. This highlights the importance of alignment and tension in chain-driven systems.
Preventive Maintenance and Chain Longevity
To extend the life of the coupling chain:

• Lubricate regularly with chain-grade oil or dry lube to prevent dust accumulation
  
• Inspect for elongation or rust every 100 operating hours
  
• Replace sprockets if teeth show signs of hooking or thinning
  
• Avoid sudden load spikes by easing into hydraulic operations
  

Chain failure is often gradual, marked by increased vibration, noise, or erratic movement. Catching these signs early can prevent downtime and costly repairs.
Final Thoughts
The John Deere 170 skid steer may be a legacy machine, but its mechanical systems remain serviceable with the right parts and attention. Replacing the coupling chain is a straightforward task, provided the correct specifications are followed and underlying issues are addressed. In a world of increasingly electronic equipment, the 170 stands as a reminder that simplicity, when maintained properly, can still deliver dependable performance. Whether clearing brush or grading gravel, a well-tuned chain drive keeps this compact workhorse moving.