A standard excavator that swings or travels slowly, whines under load or leaks oil from the swing reduction hub is usually telling you the DX380 Swing Reduction Gearbox has reached the end of its service life. Worn planet gears, a scored ring gear and a failed bearing set all waste torque before it reaches the track or the upper structure. RITO supplies this DX380 Swing Reduction Gearbox as a ready-to-fit assembly, so the machine is back to full swing torque and swing speed without a rebuild.
Item NO.:
DX380Order(MOQ):
1pcsPayment:
T/T, WESTERN UNION, CHINESE BANK,PAYPALProduct Origin:
JAPANShipping Port:
Huangpu,GuangzhouLead Time：
In StockDX380 Swing Reduction Gearbox is a complete reduction assembly for the swing circuit of standard excavators. The housing carries the ring gear and bearing bores in one rigid casting, the planet carriers run on caged bearings, and the output shaft is splined to match the original interface, so the unit drops into the existing mounting pattern without modification. Every assembly is checked for backlash, turning torque and seal integrity before it leaves the line.
| Part Number | DX380 |
| Part Name | Swing Reduction Gearbox |
| Compatible Brand | Doosan |
| Applicable Models | DX380 |
| Application | Excavator swing reduction unit in the upper structure swing circuit |
| Material | Cast iron housing with hardened alloy steel gear set |
| Product Color | Industrial grey / OEM color |
| Working Temperature | -25°C~+80°C |
| Key Function | Turns motor torque into controlled swing rotation |
| Condition | 100% New |
| Packaging | Wooden Case Reinforced Carton Neutral Packing Customized Box |
 | Rigid Cast Housing The ring gear and bearing bores sit in one casting, holding bore alignment under load so the gear mesh does not walk out of position. |
 | Tested Before Packing Each unit is checked for backlash, turning torque and seal integrity, then packed in a reinforced case to survive international freight. |
 | Complete Assembly Ring gear, planets, carriers, bearings, seals and output shaft arrive as one unit, so nothing is reused from a worn original. |
 | Matched Gear Set Ring gear and planet gears are lapped as a matched set, so tooth contact is full width from the first hour and the unit stays quiet under load. |
Q: How do I confirm this DX380 unit fits my machine?
A: Compare the mounting bolt pattern, the output spline and the overall height against the unit on your machine, and check the model plate. If the numbers differ, send us a photo of the plate and we will confirm the correct variant.
Q: What usually causes these reduction units to fail?
A: Contaminated oil and lost bearing preload. Once dust enters through a worn seal, the bearings loosen, the gear mesh misaligns and the unit starts to whine and overheat within a few hundred hours.
Q: Do I need to adjust backlash after fitting?
A: No. Backlash and bearing preload are set at assembly. Fit the unit, fill with the specified oil grade, and check for leaks after the first few hours of operation.
Q: Is this a complete assembly or just the gear set?
A: It is supplied as a complete reduction assembly - housing, ring gear, planet gears, carriers, bearings, seals and output shaft - so nothing has to be transferred from the old unit.
Q: Which oil should I use after installation?
A: Use the grade listed in the machine service manual for the final drive or swing reduction. Overfilling causes heat; underfilling causes immediate bearing damage, so fill to the level plug.
Q: Can this unit be used as an upgrade on an older machine?
A: Where the mounting pattern and spline match, the later specification can be fitted to earlier machines. Confirm the interface dimensions with us before ordering.
Q: Why Choose RITO?
A: Listed Factory
Stable&Reliable Quality
OEM Factory for Chinese Top Excavator Brands
Supplier to Fortune 500 Companies
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