Doosan DH225-7 Swing Gearbox 2nd Planetary Carrier Spider With Sun Gear Assy For Excavator Parts

Doosan DH225‑7 Swing Gearbox 2nd Planetary Carrier Spider With Sun Gear Assy For Excavator Parts
Product Overview
This complete second‑stage planetary carrier spider and sun gear assembly acts as the secondary torque reduction core component installed within the swing reducer of Doosan DH225‑7 22‑ton mid‑size crawler excavator. It receives torque output from the first‑stage planetary group, completes secondary deceleration and torque amplification, and delivers power to drive upper structure rotation. This excavator model is widely applied in earth‑moving projects, stone loading, site grading, road construction and general demolition work. Under long‑duration alternating forward‑reverse slewing impact loads, deteriorated gear oil and failed sealing elements allow construction dust and metallic wear debris to enter gearbox interior, which will bring about spline galling, gear tooth surface pitting, carrier spider bending deformation and pin‑hole oval wear. Common failure signs include distinct metallic grinding noise inside swing gearbox, intermittent jerky cab rotation, weakened swing driving force, excessive operating temperature on reducer housing, as well as metal fine particles found in waste oil during swing gear oil maintenance. Produced strictly according to OEM forging blueprints and gear meshing technical standards, this aftermarket replacement assembly supports direct drop‑in installation, and effectively prevents successive damage to other high‑cost internal gearbox components.
Technical Specification

Core Advantages

1. Forged alloy structure suited for mid‑size excavator cyclic swing impact load Carrier spider and matched sun gear are hot forged from high‑quality alloy steel blanks. After professional carburizing quenching heat treatment, gear tooth and inner spline surfaces gain high hardness meanwhile keeping proper core toughness. This assembly can endure recurring instant impact torque generated by frequent swing start‑stop and combined digging‑slew movements, lowering failure risks such as tooth chipping, spline scratch and carrier spider distortion under harsh dusty construction conditions.
2. Strictly checked gear meshing performance guarantees steady slewing operation Each finished assembly will pass tooth profile inspection and backlash detection before delivery. Precisely controlled meshing clearance cuts down transmission vibration and friction‑caused grinding noise. When the machine carries out compound actions of boom, arm, bucket and swing simultaneously, it keeps stable power output and avoids unsmooth jerky cabin rotation caused by poor gear matching precision.
3. OEM‑consistent mounting dimensions shorten on‑site repair downtime Key dimensions covering carrier outer outline, sun gear spline parameters, pin‑shaft hole layout and depth fully conform to original OEM requirements. Field service technicians can finish part replacement directly without gearbox housing modification or manual adjustment for internal fitting gaps. For equipment rental companies and local machinery repair shops, it reduces machine idle time and economic loss brought by project delay caused by swing system malfunction.
4. Stress‑relief annealing removes forging residual internal stress Stress‑relief annealing eliminates residual stress produced in hot forging procedure, improving long‑term structural stability under repeated cyclic impact loads. Cooperating with high‑precision machining on pin shaft holes and bearing mounting seats, it slows premature abrasion of matched planetary gears and bearings, prolonging overall service life of swing reduction assembly.
5. Cost‑saving partial overhaul solution for mid‑size excavator operators Rather than purchasing a whole expensive swing reducer unit, replacing only the worn second‑stage planetary carrier and sun gear assembly helps customers control maintenance budget. It is well‑received by machinery repair garages, construction contractors and global spare‑parts wholesalers focusing on Doosan mid‑size excavator business.

Manufacturing & Quality Control
Our production plant concentrates on manufacturing planetary transmission spare parts for Doosan mid‑tonnage excavator swing gearboxes. Full‑flow quality management includes raw‑material composition checking, forging appearance inspection, heat‑treatment hardness testing, gear‑tooth precision measurement, spline dimension verification and sample no‑load running‑in test. Only fully qualified assemblies can enter packaging process. Finished goods are coated with anti‑rust preservation oil, wrapped by shock‑absorbing cushion materials and packed in export‑standard fumigated wooden cases, to prevent collision deformation and rust during long‑distance sea‑land combined transportation. We support large‑volume wholesale and stable batch supply; small trial orders are acceptable for global buyers.
Frequently Asked Questions
Q1: What abnormal conditions mean inspection or replacement for 2nd planetary carrier and sun‑gear assembly? A: If your Doosan DH225‑7 excavator generates obvious metallic grinding sound inside swing gearbox, cabin rotates jerkily intermittently, swing power decreases greatly, reducer housing runs over‑hot, or metal impurities are observed in waste swing gear oil during oil‑change service, you need to disassemble swing reducer for complete internal check in time.
Q2: Can this assembly fit other different excavator models? A: This spare part is specially manufactured for Doosan DH225‑7 swing gearbox. Even if some other excavator models have similar exterior look, internal gearbox configurations may exist differences. Please double‑check corresponding OEM part numbers before placing order to prevent installation mismatch.
Q3: What important installation reminders during swing gearbox overhaul? A: Thoroughly clear all metal debris and aged residual gear oil inside swing gearbox housing prior to installation. Meanwhile examine wear degree of planetary gears, bearings and oil seals. After assembly completion, refill qualified swing gear oil, perform low‑speed no‑load swing running‑in test before putting excavator into official construction work.
Q4: Warranty scope explanation A: Our warranty is valid for defects stemming from raw‑material flaws and manufacturing errors. Damage induced by foreign‑object invasion, insufficient gear‑oil lubrication, heavy overload impact and improper disassembly‑installation will not be covered by warranty. Please strictly follow Doosan official service manual while conducting swing gearbox overhaul operations.