Travel Gearbox for Komatsu PC2000 / PC3000 / PC4000: Buyer's Guide

The short version

The travel gearbox — the final drive — is one of the highest-stress assemblies on a 200 to 400 tonne mining excavator. On a PC2000, PC3000 or PC4000 a failed final drive costs far more than the part itself: it stops a loading tool that the entire haul cycle depends on.

We build these units ourselves, in our own factory in Jining, Shandong - the same city that supplies most of the world's aftermarket hydraulic components for Japanese and Korean excavators. This guide covers what to check before buying a replacement: which part numbers apply, how to read a failure in progress, what to measure on a new unit, and how to ship something weighing several tonnes without burning a week at the port.

What the travel gearbox does on a PC2000 / PC3000 / PC4000

A mining excavator's propel system is a fully hydrostatic drive. Two independent travel gearboxes, one per track, sit at the rear of the undercarriage. Each is a two-stage combination:

1. Hydraulic travel motor — converts hydraulic flow into rotary power
2. Planetary reduction gearbox — multiplies torque down to track speed

On machines this size the assembly is not a drop-in car part. It is a machined, heat-treated, pressure-tested assembly weighing from roughly one tonne on a PC2000 to several tonnes on a PC4000. The gearbox output drives the track sprocket through a final reduction, so any internal damage propagates into the sprocket, chain and idler very quickly.

Part numbers by model

These are the assemblies we supply. Match the machine model and the variant — the -6 and -8 undercarriages do not share drives.

Still confirm before you order. Read the plate on the failed assembly, not the machine plate, and quote your serial number. Two numbers appearing against one model on this table is not an error — it reflects that both have been fitted across the PC3000-6 and PC4000-6 build range. We confirm fitment in writing against your serial number before invoicing.

How to confirm you have the right number:

1. Read the plate on the existing unit - not the machine plate. The gearbox plate carries its own assembly number.
2. Quote the machine serial number to us, not just the model.
3. Get fitment confirmation in writing, naming the serial range it covers.
4. If the unit is a ZF-built drive (common on PC3000 and above), match the ZF assembly number as well as the Komatsu number.

On the units we hold, the plate sits on the motor flange end, stamped with the assembly number. If you are unsure which number your machine carries, send us the plate photo and the serial number - we read it for you and confirm fitment the same day.

How to tell a travel gearbox is failing

Final drives rarely fail without warning. The signals come in this order:

Early stage — catch it here and you may only need a reseal or bearing set

• Oil weeping at the housing joint or around the motor flange
• Metallic sheen or grit in the drained oil
• Slightly uneven tracking, machine pulls to one side under load
• Rising oil temperature on the affected side

Mid stage — the unit needs to come out

• Audible whine or knock that changes with travel speed
• Visible play at the sprocket hub when the track is slack
• Oil analysis showing iron and chromium climbing together (gear + bearing wear)
• Repeated seal failures on the same side

Late stage — plan for a full assembly

• Sprocket will not hold position, track jumps teeth
• Motor case drain flow well above spec
• Broken teeth found on drain plug magnet

What to measure on a replacement unit

Before accepting any replacement — new, rebuilt or used — insist on these checks. A supplier who cannot answer them is not a supplier you want for a machine that costs more per hour of downtime than the part does.

Ask for the test report with the unit, not a promise of one.

Every unit we build carries a QC tag recording who assembled it, who ran the test and who signed off the air-pressure check - a paper trail on the machine itself, not in a folder somewhere.

The contact pattern is the one thing you cannot check from the outside, which is why we document it during build and keep the record with the unit.

New, rebuilt or used: how to choose

The trade-off that actually matters is not price — it is downtime cost per hour against risk of a second failure. On a PC4000 working a production bench, one day of stopped loading usually exceeds the price gap between a dealer unit and a new OEM-standard unit.

Every unit we ship is brand new, never rebuilt, never used - manufactured in our own factory in Jining, China, not bought in from a trading company and re-badged. No core return, no exchange deposit, no waiting on someone else's core to come back in. That matters when the machine is down: a rebuilt unit is only as fast as the core pipeline behind it, and a trader is only as fast as their supplier's promise.

Because we machine and assemble in-house, we can also tell you exactly what is inside the unit you are buying: gear material and hardness, which bearings, seal brand, and the test pressure it passed at. Ask a reseller those questions and you usually get a catalogue page.

Where the unit is made, and why it matters

Our factory is in Jining, Shandong Province, China - an industrial city that has become the country's centre for excavator hydraulic components. That gives us two things a trading company cannot offer:

• We control the machining. Housing bores, gear cutting, heat treatment and assembly are done in-house or by long-term local partners we have worked with for years, not sourced case-by-case from whoever is cheapest that month.
• We can answer technical questions. If you need the gear material, the hardness range, the bearing brand or the assembly backlash tolerance, we can give you the number, because we set it.

What that means for a buyer:

We are not the cheapest unit on Alibaba, and we are not trying to be. On a machine that costs more per hour to stop than the gearbox costs to buy, the cheapest unit is rarely the cheapest decision.

We get visitors. Buyers come to Jining, walk the floor, watch their unit go through test, and take the photo on the way out. If you would rather inspect before you wire money, come - that is what the door is for.

Shipping a multi-tonne gearbox without losing a week

This is where most cross-border buyers get burned, and where a supplier who ships these regularly is worth more than a supplier who is 5% cheaper.

Packing

• Export crate, not a pallet with strapping. The assembly must be bolted to the crate base, not resting on it
• Oil drained and the ports plugged and tagged
• Desiccant and VCI bag for sea freight; the seal faces are the first thing to corrode
• Lifting points marked on the crate, not just the unit

Documents

• Commercial invoice with correct HS code and the part number stated plainly
• Packing list with net and gross weight per crate
• Certificate of origin where the destination requires it
• Test report and warranty terms inside the crate, not just by email

Freight

• We ship from Qingdao port, about five hours from our factory by road. Qingdao is the main container gateway for Shandong and runs direct services to Europe, the Middle East, Southeast Asia, Africa and both US coasts, so most destinations are one sailing away rather than two.
• LCL is normal for one unit; if you are restocking, a 20ft part-load often beats two LCL bookings
• Book space early - oversized and heavy cargo gets rolled more often than standard freight
• Insure at replacement value, not invoice value
• For mining sites, confirm the destination can actually receive and unload the crate before it ships

FAQ

Which travel gearbox fits my PC3000-6?

Two numbers are in circulation for the PC3000-6: 99481640 and 89810840. Confirm from the plate on the existing unit plus the machine serial number - we will tell you in writing which one your machine takes before you commit.

Can I replace just the travel motor instead of the whole gearbox?

Sometimes — if the planetary section is healthy and only the motor has failed. The decision rests on the gear tooth contact pattern, backlash and bearing condition. If metal has circulated through the housing, replace the assembly.

How long should a travel gearbox last on a PC2000-8?

Service life depends far more on undercarriage condition, oil cleanliness and operator habit than on the part itself. Track tension out of spec and contaminated oil are the two biggest life-shorteners. Oil analysis at fixed intervals is the cheapest way to extend it.

What is the most common cause of premature final drive failure?

Contamination. Failed seals let grit in; grit destroys bearings; bearing debris destroys gears. The second most common is running with a track that is too tight.

Where are the gearboxes manufactured?

In our own factory in Jining, Shandong, China. We machine and assemble the units ourselves - they are not rebadged units bought from a trading company. That is why we can quote material, hardness and bearing specifications for the exact unit you receive.

Are the units new or rebuilt?

Every unit is brand new — never rebuilt, never a used take-off. No core charge, no exchange deposit, no return freight to arrange. You get a painted, pressure-tested assembly with its own assembly number.

Do you supply the travel motor and gearbox as a complete assembly?

We supply brand-new complete assemblies — hydraulic travel motor bolted to the planetary gearbox, tested and painted as one unit, ready to bolt on. If you only need the motor or the gearbox section on its own, tell us; it depends on availability at the time.

Before you order, send us these five things

1. Machine model and serial number
2. Photo of the data plate on the failed unit
3. Photo of the installation showing the sprocket and track frame
4. Oil sample result if you have one
5. Required delivery date and destination port

We reply with fitment confirmation, price, and an honest ship date - if a part number is not in stock, we will tell you the production lead time rather than quote a date we cannot hold.

With those five we can confirm fitment, quote, and give you a realistic freight date — usually the same working day.

Talk to the person who builds them

Send the five items above on WhatsApp and you will usually have fitment confirmation and a price the same working day. If you want to see the unit before paying, ask for a video call from the test bench - we will walk around the actual unit with the phone.