Evaluating the International TD25 Dozer: Power, Pitfalls, and Practical Considerations

The International TD25 is a heavy-duty crawler dozer introduced in the late 1970s, often compared to the Caterpillar D8K in terms of size and performance. With a ripper-equipped rear and a tilt blade, the TD25C variant offers robust earthmoving capabilities.

It features:

• Approximate operating weight: 73,000 lbs with ripper
• Two-speed steering clutches for nimble maneuvering
• Comfortable operator station for its era
• Strong performance in coal mines, quarries, and large-scale grading

While not quite in the D9 class, the TD25C is a formidable machine for mid-to-heavy excavation tasks.

Undercarriage Inspection and Wear Indicators

Before purchasing, it’s essential to inspect the undercarriage thoroughly. Key areas include:

• Track pads: A new set typically has 38 pads per side. Count and assess wear.
• Sprockets and link pins: Look for rounding, cracks, or excessive play.
• Blade trunnions: Check for lateral movement—½" to 1" play may indicate wear.
• Front idler slots: Elongation suggests undercarriage fatigue.
• Bottom rollers: Especially the front ones, which bear the brunt of impact.

In one case, a TD25 used extensively on lava rock showed significant sprocket skipping due to loose track tension and worn recoil components.

Transmission and Fluid Concerns

A major red flag emerged when the machine’s transmission was mistakenly filled with 30W detergent engine oil. After realizing the error, the owners drained it and replaced it with 30W hydraulic fluid. However, the machine still exhibited sluggish movement until warmed up—suggesting possible internal seal damage or air intrusion.

Important notes:

• TD25 transmissions do not typically use engine oil.
• Using incorrect fluid can degrade clutch packs and seals.
• Air in the system may cause delayed engagement until purged.

One technician speculated that the issue might stem from a leak around the transmission cooler or lines, allowing air to enter during shutdown.

Engine Oil Leak and Mechanical Integrity

The machine reportedly lost a quart of engine oil over just 250 feet of travel, leaving a visible trail. A puddle was found in the belly pan, indicating a substantial leak. While oil leaks are common in older dozers, this rate suggests a serious gasket or seal failure.

Combined with transmission concerns, this raises questions about the machine’s overall mechanical health.

Track Adjuster and Recoil Spring Design

The TD25 uses a recoil spring system composed of stacked Belleville washers. If the track adjuster cylinder is blown or the washers are fractured, tensioning the tracks becomes impossible. A loose track can lead to:

• Sprocket skipping
• Chain derailment
• Accelerated wear on rollers and guides

Repairing the recoil system can be costly and requires specialized knowledge.

Lava Rock Excavation: A Unique Challenge

The buyer intended to use the TD25 to flatten three acres of lava rock in Hawaii. Lava rock varies in density:

• A‘ā: Rough, broken surface; moderately workable
• Pāhoehoe: Smooth, dense flows; harder to rip
• Blue rock: Extremely dense; nearly impervious to ripping

Operators with D9G dozers reported needing multiple passes to penetrate even a few inches. A TD25 may struggle unless the rock is fractured or weathered.

Alternative Options and Cost Analysis

Given the risks, some experts recommended renting a newer machine like a Caterpillar D8T. Estimated costs:

• Daily rental: ~$2,200
• Weekly rental with mobilization: ~$7,000
• Time to complete 3 acres: potentially one day with proper equipment

This approach avoids mechanical surprises and ensures productivity.

Final Thoughts

The International TD25 is a capable machine with a loyal following, but purchasing a 1979 unit with transmission and engine issues—especially for lava rock excavation—poses significant risk. Without access to skilled mechanics or affordable parts in Hawaii, repairs could be slow and expensive. Renting a newer dozer or hiring a contractor may offer better value and reliability. For enthusiasts, the TD25 remains a nostalgic powerhouse—but for critical earthmoving, practicality must prevail.