KOMATSU 42C-20-12621 OE Part

Name: KOMATSU 42C-20-12621 OE Part
Brand: PTC Drivelines
SKU: KOMATSU 42C-20-12621

Komatsu Replacement Part

KOMATSU 42C-20-12621

OEM Test Certified Self-Lubricated 24h Quote Response ISO 9001:2015

The PTC1002 Rear Spider Assembly is designed for reliable performance under demanding conditions in the Komatsu HD785-7 Off-Highway Rigid Dump Truck for use in heavy-duty earthmoving, mining, and quarrying applications. This rear spider assembly is a replacement for OEM 42C-20-12621 and has been designed to be dimensionally correct and compatible with the spider to allow proper fit and function on the drivetrain.

The PTC1002 can withstand the high torque, impact loading, vibration, and repeated loading and unloading stresses from fully loaded haul cycles. With its high durability, it can ensure the smooth movement of the driveline and minimize component wear and equipment failures.

Good quality of precision manufacturing and component geometry assist in smooth rotation and reliable load distribution in the driveline. The assembly will also be suitable for rough haul road conditions, exposure to moisture, slurry, dust, and other harsh working conditions. The PTC1002 Rear Spider Assembly can help maximize equipment uptime, component life, and maintenance—all because of reliable power transmission at the rear driveline.

Technical Specifications

Specification	Details
Part Name	Spider Assembly - Rear
Part Number	PTC1002
OEM Reference Number	42C-20-12621
Application	Komatsu HD785-7 Off-Highway Rigid Dump Truck
Position	Rear Driveline
Component Type	Rear Spider Assembly
Construction	Heavy-Duty Engineered Construction
Load Capability	Suitable for Heavy-Duty Driveline Applications
Resistance	Torque, Vibration, Impact, and Repeated Mechanical Stress
Operating Environment	Mining, Quarrying, and Heavy Construction
Fitment	Replacement for the Specified OEM Application
Recommended Use	Severe-Duty and Continuous Operating Conditions
Function	Supports Driveline Movement and Torque Transmission

Frequently Asked Questions

Is the PTC 1002 the same physical spider for both my WA800-3 and a WA900-3, or do these loaders need different parts?

It's the same part for both — OEM 42C-20-12621 covers the front-and-centre position on the WA800-3 and WA900-3 alike, so there is no separate variant to choose between depending on which of the two you're running.

Why does this position seem to wear faster than other joints on my WA900-3?

The front-and-centre spider sits close to the transmission output, so it takes the initial hit from every hard dig or heavy bucket load before that torque is distributed further down the driveline. That earlier position in the load path is often why operators notice wear here before other joints.

What's the earliest sign I should watch for on a WA800-3 before this spider fully fails?

A gradual increase in play at the joint or a low-frequency vibration felt through the cab during heavy digging are the usual early indicators. Catching it at that stage means a straightforward spider swap instead of risking damage to the surrounding driveshaft or yoke.

Does the PTC 1002 require any different handling on a WA900-3 compared to a WA800-3 given they're different loader sizes?

No — installation is the same standard process regardless of which of the two models it's going into, since the joint geometry and fitment at this position are identical across both.

Can I request a dimensional drawing for OEM 42C-20-12621 before ordering the PTC 1002 for my WA800-3 or WA900-3?

Yes. Every PTC 1002 batch is checked against OEM drawings before shipping, and we can provide a certified dimensional drawing or full inspection report on request — just reference OEM number 42C-20-12621 or PTC 1002 along with your loader model when you contact us.