Two-Speed Track Not Working

[MikePhua]

A classic scenario: a compact 2001 New Holland EC35 arrives on the jobsite and the operator flips the “hare” symbol switch expecting the machine to sprint into high-speed mode—but nothing happens. Power is present at the switch and even travels through the red-yellow wire down to a plug beneath the control panel—but beyond that plug, there’s simply no wiring at all. The circuit just stops. Suddenly the operator wonders: was the two-speed function even installed at the factory or can it be retrofitted?
This is more than a missing wire—it’s a case of dormant functionality waiting for completion.
Machine Lineage and Development History
The EC35 mini excavator traces its roots to the late 1990s. It’s a rebadged version of a Terex TC35, built under New Holland’s Construction Equipment umbrella. It typically carried a Mitsubishi S4L2 engine, or sometimes S412 variants, in the early models, before later Refreshed versions adopted CNH-sourced powerplants.
New Holland produced these from about 1999 through the mid-2000s—used globally in landscaping, farm cleanup, trenching, and other general-purpose excavating tasks.
Machine Specifications and Market Performance
Drawing from technical datasources:

• Operating weight hovers around 3.4 t (3,400 kg), with transport dimensions approximately 5.15 m long, 1.5 m wide, and 2.52 m tall. Rubber tracks (300 mm wide) and a front blade were available options.
  
• Bucket lift power is modest—tear-out force about 22 kN, reach roughly 5.5 m, dredging depth about 3.4 m.
  
• Transport/export versions in North America were often listed at around 7,500 lb (≈3.4 t), 16 ft 11 in long, 4 ft 11 in wide, 11 ft 5 in tall.
  
• An auction snapshot from early 2025 shows machines of similar class (up to 12,000 lb) with net 32 HP engines and resale prices in the $17,900 range.
  

Though New Holland didn’t publicize large-scale sales figures for the EC35, it was adopted by smaller contractors, farms, and rental fleets—solidifying its niche due to compact size and dealer network reach.
Glossary of Terms and Jargon

• Two-speed track: The dual travel modes—“hare” for faster transport, “turtle” for precise digging.
  
• Tear-out force: The resistance the bucket can overcome when prying into material.
  
• Dredging depth: How deep below ground level the arm can dig.
  
• Rebadged: A model manufactured by one company and sold under another brand with minimal changes.
  
• Track width: Width of the individual track shoe—300 mm balances footprint with mobility.
  
• Transport dimensions: Size of machine when loaded for hauling.
  

Expanded Context: Industry Narratives
Imagine an owner named Sam who picked up a 2001 EC35 to clean up woodland trails on his rural Kentucky property. He flipped the high-speed lever expecting the machine to roar forward—but the undercarriage just trudged along. Curious, Sam traced the wiring only to find the telltale red-yellow cable ending abruptly. His neighbor chuckled: “Looks like they skipped wiring the other side.” It reminded Sam of a news story he once read about how some assemblies shipped without optional features activated, saving initial assembly cost and letting distributors enable them later if customers displayed demand.
Possible Wiring Fixes and Technical Advice
Here’s how to resolve a missing two-speed function:

• Confirm factory fit: Some EC35s never had the two-speed option fitted—check original build sheets or a parts catalog to see if the control panel switch was wired to a speed control valve.
  
• Trace the plug: If a plug exists under the panel with only one wire, it may be a factory-provisioned connection point intended to facilitate later installation.
  
• Install missing wiring: Run a proper gauge wire from the plug location into the valve block where the two-speed hydraulic solenoid lives. Add appropriate fuse or relay protection.
  
• Test hydraulic pressure: Ensure hydraulic fluid is clean and set to spec; contaminated oil can hinder diverter valve operation.
  
• Inspect relief or control valve: A stuck or missing valve can block the high-speed circuit—clean, rebuild, or replace as needed.
  
• Source parts: Owners have reported difficulty obtaining cylinder-specific seal kits when buying through New Holland—they’re often bundled in expensive kits with irrelevant parts. Shop local hydraulic rebuilders for better value on seals and components.
  

Suggestions and Practical Recommendations

• Safety first: De-energize the electrical system before working under the dash; follow standard maintenance rules as laid out in repair manuals.
  
• Track tension check: Before testing speeds, ensure tracks are adjusted correctly—1.0 to 1.38 in sag between roller and track is ideal.
  
• Spend wisely: If two-speed isn’t essential, consider leaving it dormant—but if desired, install components using sourced parts rather than costly OEM kits.
  
• Document the fix: Label added wiring and note configuration changes in a service log for future maintenance.
  

Closing Thoughts
In essence, the “hare” lever in a New Holland EC35 may occasionally be dead silence due to a missing circuit or dormant hydraulic circuit. But with careful diagnosis, understanding of the machine’s heritage as a Terex-derived unit, and hands-on wiring and valve work, that bolt-on function can spring to life. For farmers, contractors, or equipment renovators, reviving two-speed travel can transform an undercarriage into a more efficient, versatile machine—turning a curious quirk into practical advantage.