M5X250 Swing Motor Gearbox Rotary Reducer for SDLG 6400F Mining Excavators
This swing motor gearbox (rotary reducer) is built around the M5X250 swing motor unit and installs on the SDLG 6400F excavator. The housing carries a hardened planetary gear train, a matched bearing set and high temperature oil seals, so the swing function keeps its smooth braking and steady rotation instead of drifting, grinding or leaking oil after long shifts. It suits contractors working mining benches, quarry faces and heavy earthmoving sites where the machine swings continuously under load.
Unit Specifications
| Item | Detail |
|---|
| Swing motor model | M5X250 |
| Part name | Swing motor gearbox / rotary reduction gearbox |
| Machine model | SDLG 6400F excavator |
| Assembly includes | Swing motor, planetary gear set, output shaft, bearing set, oil seals, housing cover |
| Gear material | High hardness wear resistant alloy steel, heat treated |
| Bearings | Premium grade bearing set, pre-loaded on assembly |
| Oil seals | High temperature resistant seals for continuous duty |
| Condition | New aftermarket replacement unit, run-in tested |
| Packing | Foam wrapped, export wooden case |
Why This Unit Holds Up in Mining Duty
- Hardened gearing — tooth surfaces are heat treated to resist pitting and wear under repeated swing load, so backlash stays within tolerance far longer than soft gears
- Premium bearings — matched bearing set carries the axial and radial load of the swing column without play or rumble
- High temperature oil seals — seals keep their shape when the gearbox runs hot for hours, which is the usual cause of oil seepage and bearing failure on mining machines
- M5X250 motor match — the reduction gearbox is built to the M5X250 swing motor mounting pattern, so motor and gearbox work as one unit without adapter plates
- Run-in tested — every unit is turned and checked before packing, so abnormal noise or tight spots are caught in our workshop instead of on your jobsite
- Direct fitment — mounting flange and output spline match the SDLG 6400F installation, no machining needed on site
Typical Symptoms This Unit Fixes
- Slow or weak swing, machine struggles to turn under load
- Grinding or knocking noise from the swing area
- Oil leaking from the swing motor or gearbox housing
- Play in the swing column or drifting when the joystick is released
Installation Notes
- Confirm the machine model plate matches SDLG 6400F and the old motor plate reads M5X250 before ordering; if the machine is a different serial range, send us photos of the old nameplate and flange for verification
- Drain and replace the swing gearbox oil at the same time, and flush the housing if metal particles are found
- Check the swing brake valve and relief pressure setting; an over-high relief pressure can damage a new gearbox within a short time
- Re-torque mounting bolts to the workshop manual value and recheck oil level after the first 50 working hours
Packing and Shipping
Each unit is drained, plugged, wrapped in anti-rust film and shock absorbing foam, then fixed inside an export wooden case with steel banding. We ship by sea, air or express depending on order size, and supply the packing list, commercial invoice and photos of the packed case before dispatch.
FAQ
Q: Is M5X250 the complete motor and gearbox?
A: The unit is supplied as the M5X250 swing motor with its reduction gearbox assembly. Tell us if you only need the gearbox or only the motor, and we will quote the matching option.
Q: Is this a genuine SDLG part?
A: It is a new aftermarket replacement unit produced to fit SDLG 6400F machines, priced well below dealer parts while keeping the same mounting dimensions.
Q: What is the minimum order quantity?
A: One set is acceptable for trial orders, and we offer better pricing for repair workshops and fleet maintenance buyers ordering in batches.
Q: How long is the lead time?
A: Usually 3 to 7 working days for stock units, and 15 to 25 days for production orders, depending on quantity.
Regional Buyer FAQ
North America and Europe
Q: Do you supply CE or EPA documents?
A: The gearbox is a replacement component, not a CE-marked machine, so machine-level CE or EPA certificates do not apply. We can provide material certificates, dimensional inspection reports and the commercial documents your customs broker needs.
Q: How is the wooden case handled for import clearance?
A: Cases are heat treated and ISPM 15 marked, and we send packing photos plus the packing list before dispatch so the shipment clears without a wood packaging hold.
Q: Can you supply a repair kit instead of the complete unit?
A: Yes. Bearings, seals, shafts and gear sets can be quoted separately for workshops that rebuild units in house, and we mark each part so it matches the M5X250 reduction gearbox.
Middle East and Gulf
Q: Will the seals survive high ambient temperature and dust?
A: The unit uses high temperature resistant oil seals, and we recommend the seal grade for machines running above 45 C ambient. For dusty sites we also suggest checking the breather and oil change interval at every 500 hours.
Q: Do you accept L/C for larger fleet orders?
A: Yes, we work on T/T and L/C, and for repeat fleet buyers we can hold stock against a rolling delivery schedule.
Southeast Asia
Q: How do you prevent rust during sea freight in the rainy season?
A: Units are drained, plugged and wrapped in anti-rust film before foam and wooden case packing, which is the standard protection for humid destinations. Desiccant bags are added on request.
Q: Can I start with a small trial order?
A: One set is fine for a first order, and LCL shipping can be arranged together with other parts such as hydraulic pumps or travel motors to save freight.
South America
Q: Is the unit suitable for high altitude mines?
A: The gearbox is mechanical and does not lose capacity with altitude. What we do recommend is confirming the hydraulic oil viscosity and relief pressure setting on machines working above 3000 m so the swing motor and gearbox stay within their design load.
Q: Can you provide Spanish documents?
A: Yes, we can issue the packing list, invoice and installation notes in Spanish on request.
Africa
Q: Our workshop has limited tooling, is the unit plug and play?
A: The flange and output spline match the SDLG 6400F installation, so the change is a bolt-on job. We supply a step-by-step installation note and can send photos of the mounting face before shipping.
Q: Can you include the common wear parts in the same shipment?
A: Yes. Seals, bearings and coupling parts are frequently added to the same case so one shipment covers a full repair.
Russia and CIS
Q: How does the unit behave in low temperature?
A: Cold start performance depends mainly on the hydraulic oil grade. We mark the recommended oil viscosity on the packing note and can supply low temperature seals if the machine works below -25 C.
Q: Which documents are provided for customs?
A: Commercial invoice, packing list, certificate of origin on request, and the technical description sheet for the gearbox, so the goods can be classified correctly at import.
About Us
We focus on after-market hydraulic maintenance and replacement parts for construction machinery, covering hydraulic pumps, travel motors, swing motors, control valves, gear pumps and related gearbox components for excavators, rotary drilling rigs, pile drivers, concrete mixers, pump trucks, cranes and harvesters. Our workshop supplies both single-part repair orders and full overhaul kits.
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