International Harvester TD15B Turbo Bulldozer Detailed Overview

[MikePhua]

Machine Background and Engine
The International Harvester TD15B is a classic industrial crawler tractor widely used in heavy construction, site development, and earthmoving applications during the 1960s and 1970s. It features a powerful 6-cylinder turbocharged International diesel engine, with boost enhancing power output for demanding jobs. The engine displacement is around 5.9 liters (360 cubic inches), delivering approximately 115 to 125 horsepower, depending on configuration and tuning.
Powertrain and Hydraulics

• The TD15B bulldozer includes a 4-speed torque converter transmission providing smooth power delivery and flexibility across different working speeds.
  
• The torque converter facilitates power multiplication, enhancing low-speed torque critical for pushing heavy loads.
  
• Hydraulic system uses an open-center design with an operating pressure around 1850 psi and a pump capacity near 22 gallons per minute, powering steering, brakes, and blade control functions.
  
• The drive system encompasses planetary final drives with reliably designed crawler tracks to maintain traction on rough and uneven terrain.
  

Dimensions and Operational Details

• Operating weight ranges between 22,200 to 22,700 pounds (~10,000 kg).
  
• Track width commonly set at 18 inches, contributing to ground pressure suitable for soft to moderate terrain.
  
• The machine’s dimensions are optimized for stability during earthmoving with a strong protective operator platform.
  

Maintenance and Parts Availability

• TD15B parts remain in circulation through specialty suppliers offering new aftermarket, used, and rebuilt components.
  
• Critical components such as turbochargers, engines, transmissions, and hydraulic cylinders are serviceable with available kits and OEM-level replacements.
  
• Regular maintenance of turbocharger components, including inspection for wear or damage, helps preserve engine efficiency.
  
• Operators note linkage adjustments in the steering system are necessary when steering effort hardens.
  

Notable Historical and Practical Insights

• The TD15B played an instrumental role in the mechanization of heavy construction in its era, competing with contemporaries like Komatsu and Caterpillar.
  
• A small but dedicated community of restoration enthusiasts continues to preserve and operate these machines, showcasing their robust engineering.
  
• Compared to later models, the TD15B’s simple mechanical systems contribute to easier diagnostics and repairs.
  

Glossary of Terms

• Torque Converter: Hydraulic coupling increasing torque during low speed for better load handling.
  
• Open-Center Hydraulic System: System where fluid flows through the pump to the tank at low pressure unless actuated.
  
• Planetary Final Drives: Gear system distributing engine power efficiently to the crawler tracks.
  
• Turbocharger: Device that forces additional air into the engine for increased power output.
  
• Crawler Tracks: Continuous tracks providing traction and load distribution over soft or uneven terrain.
  

Conclusion
The International Harvester TD15B turbo bulldozer remains a symbol of durable, powerful earthmoving machinery from its period. Its robust turbocharged engine and reliable hydraulic and powertrain systems allow effective operation in challenging work environments. Continued parts availability and a fresh appreciation by restoration enthusiasts help keep this model relevant among vintage heavy equipment collectors and operators worldwide.