Komatsu PC35MR-2 Final Drive Travel Motor Assembly – HMV35 (OEM 20T-60-71120 / 20T-60-71121)

Tatan Machinery supplies 100% Brand New HMV35 complete final drive travel motor assemblies (OEM part numbers: 20T-60-71120 / 20T-60-71121, interchangeable with 20T-60-71122 / 20T-60-71110) engineered for Komatsu PC35MR-2, PC35MR-3, and PC30MR-2 tight-tail mini excavators. Powering rubber or steel crawler tracks across tight urban worksites and demolition rubble, this drop-in track drive assembly combines a two-speed variable axial piston motor with a high-ratio planetary reduction gearbox. Supported by our 12-Month Comprehensive Replacement Warranty, each assembly is completely bench-tested for gear backlash, duo-cone floating seal air retention, and automatic two-speed shift response.

Supplier Information & Build Status

When to Replace the Final Drive on Komatsu PC35MR-2: Field Diagnostics

Compact 3.7-ton zero-tail excavators frequently execute tight spin-turns and work in demolition debris. When catastrophic track drive failure strikes, replace the complete assembly under these severe symptoms:

• Tracking Deviation & Loss of One-Side Drive Force: The machine pulls heavily to one side when tracking straight, or completely fails to climb trailer ramps. Internal HMV35 motor valve plates are scratched, causing high-pressure oil to bypass directly to tank.
• Duo-Cone Floating Face Seal Ingress & Gear Seizure: Mud, demolition wire, or roots packing into the sprocket hub cut the mechanical face seals. Once gear oil drains unnoticed, planetary sun gears and needle roller bearings run dry, welding the reduction hub solid.
• Two-Speed Shift Failure (Rabbit / Turtle Mode Jammed): The excavator refuses to engage high-speed travel or chatters violently when shifting. Internal motor shift control pistons are jammed with contaminated hydraulic oil.
• Hydraulic Case-Drain Pressure Blowout: High-pressure hydraulic oil leaking past the motor output shaft seal into the planetary gearbox, over-pressurizing the gear cavity and blowing oil past the sprocket face seal.

Workshop Bench Testing & 12-Month Warranty Guarantee

Every 100% Brand New 20T-60-71120 final drive supplied by Tatan Machinery comes backed by a 12-Month Comprehensive Replacement Warranty. Before export packaging, our technicians complete a 5-point quality validation:

1. Planetary Gear Mesh & Backlash Check: Optical dial indicator inspection of planetary gear clusters to confirm smooth rolling contact and eliminate premature gear chipping.
2. Two-Speed Shift Hydraulic Pressure Verification: Testing the swashplate shift piston actuation between low-speed (high-torque) and high-speed modes under full operating pressure.
3. Counterbalance Valve Dynamic Braking Test: Checking the counterbalance spool to ensure smooth downhill track braking without free-wheeling runaway.
4. Duo-Cone Floating Seal Air Hold Test: 1.5 bar pneumatic air decay test on the planetary hub cavity to certify 100% seal integrity before gear oil filling.
5. Track Frame Pilot & Sprocket PCD Measurement: CMM coordinate check on track frame mounting bolt patterns and sprocket bolt holes to guarantee 100% bolt-on alignment.

Export Heavy-Duty Packaging Process

Although compact, the 58 kg PC35MR-2 final drive requires reinforced industrial packaging to survive ocean transit without shift or moisture penetration:

• 100% Sealed Metal Port Caps: Main travel feed ports, case drain line, and 2-speed pilot shift ports sealed with heavy-duty metal blanking caps.
• Anti-Corrosion Wax Coating: External bare hub surfaces, sprocket mounting faces, and bolt threads coated with heavy marine anti-rust wax.
• Custom Internal Structural Timber Cradle: The drive unit is bolted down upright to high-density solid wood base skids to prevent tipping.
• ISPM 15 Fumigation-Free Solid Plywood Box: Fully enclosed export crate banded with multiple high-tensile galvanized steel straps.

Actual sealed port caps and heavy-duty crating for 20T-60-71120 final drive assembly

Global Shipping & Customs Documentation

Direct international dispatch tailored for commercial contractors and parts distributors:

• Emergency Machine Down Air Cargo: Fast air express via DHL Aviation, FedEx Freight, or international airlines within 3–7 business days.
• Consolidated Ocean Sea Freight (LCL / FCL): Direct containerized shipping to worldwide commercial ports.
• Clean Customs Clearance Paperwork: Commercial Invoices with correct HS Code (8483.40 – Gears & Reduction Units / 8412.29 – Hydraulic Motors), Packing Lists, and Certificates of Origin for tariff optimization.

Container loading and air freight dispatch supported by global logistics partners

Critical Installation Guidelines (PC35MR-2 Final Drive Technician Checklist)

To prevent instant failure and protect your 12-month warranty, technicians MUST adhere to these critical procedures:

1. MANDATORY: Pre-Fill Planetary Gearbox Oil Before Operation: Final drives are shipped dry or with test oil. Rotate the hub until one drain plug is at the 12 o’clock position (fill) and one is at the 3 o’clock position (level). Fill with clean SAE 80W-90 gear oil until oil weeps from the level plug! Starting with dry gears will destroy the planetary train in 50 meters!
2. Pre-Fill Motor Casing with Clean Hydraulic Oil: Disconnect the case-drain line and pour clean hydraulic oil into the motor housing before connecting the hose. Dry-starting the hydraulic motor will instantly burn out the slipper shoes.
3. Sprocket Bolt Torque & Threadlocker: Clean the track drive sprocket mating face. Apply Loctite 271 high-strength threadlocker to all sprocket bolts and torque strictly in a criss-cross pattern.
4. Verify Case-Drain Line Pressure: Ensure the case-drain line back to the swivel joint and hydraulic tank is completely unobstructed. Any backpressure over 0.3 MPa will blow out the motor main shaft seal into the planetary gearbox!
5. Low-Speed Track Air Bleeding: Elevate the track using the boom. Run the track in forward and reverse at low idle for 5 minutes without load to purge all trapped air from the hydraulic lines.

Buyer Frequently Asked Questions (Purchasing FAQ)

🔗 Frequently Purchased Together with Komatsu PC35MR-2 Final Drive:

• DIESEL ENGINE:
  Komatsu PC35MR-2 3D88E Diesel Engine Assembly (22F-01-21101)
  Remanufactured
• MAIN VALVE:
  CLSS Main Control Valve Assembly (709-70-51200) for Komatsu PC35MR-2
  100% Brand New
• HYDRAULIC PUMP:
  Main Hydraulic Pump Assembly (708-1S-00021) for Komatsu PC35MR-2
  100% Brand New
• SWING MOTOR:
  Hydraulic Swing Motor Assembly for Komatsu PC35MR-2
  100% Brand New
• BRAND CATALOG:
  View All Komatsu Excavator & Heavy Equipment Parts Collection

Get Wholesale Factory Quote for PC35MR-2 Final Drive 20T-60-71120

Looking for direct factory pricing, stock availability, or 12-month warranty terms for Komatsu PC35MR-2 travel drives? Contact senior specialist Gavin now!

💡 Fast Quote: Send your machine serial number or current travel motor photos for an accurate match within 10 minutes!