A ZX330-3ZX330-5G Swing Gearbox that has covered high hours will usually show it through noise on swing, oil weeping past the seals and a drop in swing torque and swing speed. Replacing the whole assembly is faster and more predictable than replacing gears one by one. RITO supplies the complete ZX330-3ZX330-5G Swing Gearbox for standard excavators, tested for backlash and preload before packing.
Item NO.:
ZX330-3 ZX330-5GOrder(MOQ):
1pcsPayment:
T/T, WESTERN UNION, CHINESE BANK,PAYPALProduct Origin:
JAPANShipping Port:
Huangpu,GuangzhouLead Time:
In StockRITO supplies the ZX330-3ZX330-5G Swing Gearbox as a factory-assembled reduction unit for the swing drive of standard excavators. Because the ring gear, planets and bearings are matched as a set, the assembly avoids the noise and heat that follow a partial rebuild, and the pre-set bearing preload removes the need for field shimming. Mounting holes, output spline and overall envelope follow the original dimensions so existing guards and hoses still fit.
| Part Number | ZX330-3ZX330-5G |
| Part Name | Swing Gearbox |
| Compatible Brand | Hitachi |
| Applicable Models | ZX330-3ZX330-5G |
| Application | Excavator swing gearbox 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 |
Factory Preload Bearings are shimmed and preloaded on the assembly line, which removes the end float that causes noise and premature wear in field rebuilds. | |
Double-Lip Sealing A double-lip output seal plus O-ring joints keep abrasive dust out of the oil, the main reason reduction units fail early on demolition and quarry work. | |
Bolt-On Fitment Mounting pattern, output spline and overall envelope follow the original unit, so the assembly installs with the existing bolts, hoses and guards. | |
Hardened Internals Gears and shafts are case hardened and ground, giving a tooth surface that resists pitting under the shock loads typical of excavator travel and swing duty. |

Q: How do I confirm this ZX330-3ZX330-5G 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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