Key Takeaways

• One unit, two jobs: The TM40 is not just a motor — it is a hydraulic travel motor plus planetary reduction gearbox in one assembly.
• 20-ton standard: Built for 18-25 ton excavators across Hyundai, Doosan, Volvo, Sany, XCMG, LiuGong and similar brands.
• Bolt patterns matter: Standard fit uses 30 track holes (36 mm) and 30 sprocket holes (63 mm); SH200-1 and R210-7 builds use 22 sprocket holes.
• Weight and packing: 298 kg net, shipped in a 52 x 52 x 60 cm crate.
• Built-in control: Integrated two-speed shifting and parking brake give smooth starts, stops and precise machine control.
• Failure signature: Slow travel, slope slippage, abnormal noise and case oil leaks point to the travel motor, the gearbox, or both.

Table of Contents

1. What Is the TM40 Travel Assembly?
2. TM40 Travel Assembly: Specifications
3. Bolt Patterns and Machine Fitment
4. Symptoms and Diagnosis
5. Two-Speed Shift and Parking Brake
6. New vs Rebuilt vs Aftermarket
7. Installation and Maintenance
8. Typical Export Scenario (Illustrative) and About OTTO Parts
9. Frequently Asked Questions
10. Conclusion and How to Order

1. What Is the TM40 Travel Assembly?

Every crawler excavator walks on four travel assemblies — one at each corner of the undercarriage. Each TM40 unit combines a hydraulic travel motor with a planetary reduction gearbox: the motor turns hydraulic pressure into rotation, and the planetary stages multiply torque while reducing speed before the sprocket drives the track. That is why a 20-ton machine can push itself up a steep, muddy slope using relatively small hydraulic motors.

The TM40 is the catalog model name for this two-speed, brake-equipped travel drive widely fitted on 18-25 ton excavators. Because the same assembly class is used across Hyundai, Doosan, Volvo and Chinese brands, the aftermarket interchange list is long — Hyundai machines, for example, cross the TM40 with part numbers 31N9-40020, 31N9-40040, JMV147, GM35 and GM40. Understanding that interchange is the first step to buying the right unit instead of the wrong box.

2. TM40 Travel Assembly: Specifications

Specifications as listed on the OTTO TM40 product poster; confirm hole patterns and flanges against the removed unit before ordering.

3. Bolt Patterns and Machine Fitment

Travel assemblies look alike from two meters away — and bolt patterns are exactly what separates a direct swap from a weekend of fabrication. The TM40 base configuration bolts to the track frame with 30 holes at 36 mm, and to the sprocket hub with 30 holes at 63 mm. Machines in the SH200-1 and R210-7 class instead use the 22-hole sprocket pattern, so the sprocket hub count must always be verified against the old unit, never assumed from the machine brand alone.

For the exact Hyundai R210LC-7 or R250LC-7 build, order the dedicated R210LC-7 travel motor assembly rather than guessing from the -9 interchange list. Volvo EC210 and EC210B owners should match the complete EC210 travel motor assembly by serial number, because pilot and flange details differ between EC210B, EC210C and LC variants.

4. Symptoms and Diagnosis

Diagnosis order matters. Both sides slow usually points upstream (pilot or main pump); one side weak almost always points to that side's travel assembly. Test the travel motor with a case-drain flow check before pulling the unit — if case drain is high, the motor core is leaking internally; if it is low, the problem may sit in the planetary gearbox or brake instead.

5. Two-Speed Shift and Parking Brake

The TM40 integrates two-speed shifting and a parking brake into the motor housing. The shift spool directs oil to change the motor's displacement: low speed for high torque digging and travel on steep slopes, high speed for roading between work areas. The spring-applied, hydraulically released parking brake holds the machine on gradients when the pilot pressure drops — which is why a machine that creeps downhill after shutdown is usually a brake problem, not a pump problem.

Inside the motor, the rotating group sits against a valve plate that distributes oil to the pistons. When that travel motor valve plate wears, efficiency drops and the machine loses travel power long before total failure. In a rebuild, replacing the valve plate, pistons and seals is usually cheaper than a complete new motor — and for the 20-ton class, OTTO stocks these internals separately for Sany SY215/230/235 and other travel motor builds.

1. High torque output. Stable, reliable travel on steep slopes, mud and complex conditions.
2. Smooth two-speed control. Integrated shifting gives precise machine control with smooth starts and stops.
3. Wear-resistant build. Fits 18-25 ton machines with high assembly precision and a low failure rate.

6. New vs Rebuilt vs Aftermarket

One caution from the parts room: not every "TM40" is the same unit. Older 20-ton Komatsu machines such as the PC200-3 run the TM40B variant, so a base TM40 for a Hyundai or Doosan will not bolt up. For those machines, match the TM40B travel gearbox by its own casting numbers — the letter suffix changes the mounting and the ratio.

7. Installation and Maintenance

• Measure twice, order once. Count the track and sprocket holes, measure the pilot and flange, and photograph the old unit's ID plate before ordering.
• Flush the travel circuit. Contaminated oil and metal debris from the failed unit will damage the new assembly fast.
• Use the correct oil. Fill the gearbox to spec with the recommended grade; under-filling kills planetary bearings quietly.
• Bleed the motor. Air in the travel circuit causes jerky, noisy travel — bleed both sides after installation.
• Test on a slope. After the swap, verify the parking brake holds on a gradient and both travel speeds engage cleanly.

8. Typical Export Scenario (Illustrative) and About OTTO Parts

Illustrative scenario (not a specific customer record): A quarry contractor in Southeast Asia running two Hyundai R210-7 machines found one side crawling at half speed on every grade. A local shop quoted a full undercarriage overhaul, but a case-drain test pointed to the travel motor alone. The contractor photographed the sprocket hub (22 holes), matched the TM40-class unit, ordered the complete assembly from OTTO with a spare seal kit, and had the machine walking normally within two days of the crate arriving. The lesson: correct diagnosis plus correct hole-pattern matching keeps a 20-ton machine working instead of parked.

About OTTO Parts. OTTO EXCAVATOR PARTS CO., LIMITED, established in Guangzhou, China in 2001, is an export specialist for excavator spare parts — travel motors, final drives, hydraulic pumps, swing motors, control valves, engines and undercarriage components for Hyundai, Doosan, Volvo, Komatsu, Sany and other brands. Every OTTO travel assembly ships with a 12-month warranty, test documentation and export packing. Browse the full range at www.otto-parts.com.

9. Frequently Asked Questions

Q1. What is a TM40 travel assembly?

The TM40 is a two-speed hydraulic travel motor combined with a planetary final-drive gearbox, supplied for 18-25 ton excavators such as Hyundai R210-7, Doosan DX225 and Volvo EC210B.

Q2. Which excavators does the TM40 fit?

Hyundai, Doosan, Volvo, Sany, XCMG, LiuGong and similar 18-25 ton machines; confirm the hole pattern and serial number for your exact build.

Q3. How many bolt holes does the TM40 have?

The standard fit has 30 track holes of 36 mm and 30 sprocket holes of 63 mm; SH200-1 and R210-7-class machines use 22 sprocket holes.

Q4. How much does the TM40 weigh?

The complete assembly weighs 298 kg and packs into a 52 x 52 x 60 cm crate — plan lifting gear and freight accordingly.

Q5. Is TM40 the same as 31N9-40020 or JMV147?

These are interchangeable catalog numbers for the same Hyundai R-series travel drive family — 31N9-40020 and 31N9-40040 cross with JMV147, GM35, GM40 and TM40 in the aftermarket.

Q6. My excavator travels slow on one side — motor or gearbox?

Run a case-drain flow test on the slow side. High case-drain flow means the motor is leaking internally; low flow with noise points to the planetary gearbox or brake.

Q7. Why does my machine creep downhill after shutdown?

The TM40 parking brake is spring-applied and hydraulically released. Creep usually means low brake release pressure, worn friction plates, or a stuck release circuit — check the brake before the pump.

Q8. Can I rebuild a TM40 instead of replacing it?

Yes — replacing the valve plate, pistons, seals and bearings is often far cheaper than a new unit. OTTO stocks travel motor internals for the 20-ton class.

Q9. What documents come with an OTTO travel motor order?

Packing list, commercial invoice and inspection report; certificate of origin and insurance are available on request.

Q10. What warranty does OTTO offer on the TM40?

A 12-month warranty covers manufacturing defects, with free replacement parts for any quality problem during the warranty period.

10. Conclusion and How to Order

The TM40 travel assembly is the part that keeps a 20-ton excavator moving — literally. Know the bolt patterns (30 x 36 mm track holes, 30 or 22 sprocket holes), diagnose with a case-drain test before you buy, and choose a verified assembly backed by a real warranty.

OTTO PARTS, OTTO PRICE, OTTO NOW. Send photos of the old unit — flange, sprocket hub and ID plate — and OTTO Parts will reply with a quotation within 24 hours. Complete TM40 travel assemblies with 12-month warranty ship worldwide.