229 parts · 21 makes
Swing Drives
Swing reduction gearboxes and motor assemblies for the house rotation circuit.
Know the part before you order.
The swing drive rotates the upper structure. It sees constant start-stop reversing loads, which punishes weak gear steel faster than steady-state duty ever will.
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Specified by DYCO: alloy grade, heat-treat target, seal and bearing grade. Country of origin, stated in writing. How a DYCO part is built →
Warranty — 1 year. Returns run 30 days from purchase, dealer to DYCO. A return and a warranty claim are different things — both are on the warranty and returns page →
Before you buy one
Drive, or the bearing it turns on?
Two parts, DYCO supplies both, and their symptoms overlap: play at the boom, a knock on direction change, movement that should not be there. Telling them apart before ordering is the difference between fixing it and paying twice.
Rock the house and watch the movement
Both produce play, and they cost very different money. The movement is either at the pinion mesh or in the joint between the upper structure and the car body.
The drive is a gearbox with a pinion. The bearing is a hardened raceway carrying the whole weight of the upper structure. DYCO-TP-105 — Induction-Hardened Raceways in Slewing Ring Bearings →
Check the mounting joints before anything internal
The drive bolts to the house, and the bearing bolts to both house and car body. This is the cheapest thing on the list and the easiest to skip.
A joint that has lost preload produces movement that reads as internal wear. A fastener that has already yielded will not come back by torquing it again. DYCO-TP-109 — Preload and Fatigue in Slewing Ring and Final Drive Bolted Joints →
Two lubrication systems, two different answers
Grease gone hard, gritty or missing is a ring-gear problem. Metal in the gearbox oil is the drive’s. Not the same fault, and not the same invoice.
The ring gear mesh is greased and open to the weather. The drive’s reduction gearbox holds oil and is sealed. DYCO-TP-114 — Grease Lubrication of Slewing Rings: the Raceway and the Open Gear Mesh →
Is the swing brake actually holding?
A house that creeps when it should be held gets blamed on the drive. The brake is the thing to rule out first.
A swing brake holds the upper structure against gravity, which on any kind of slope is a real load rather than a parking convenience. DYCO-TP-108 — Spring-Applied Wet Multi-Disc Parking Brakes in Travel and Swing Drives →
Look at the teeth in mesh, both sets
Fitting a new pinion against a worn arc simply moves the problem to the new part. Pinion and ring gear wear as a pair.
They wear where the machine works: the arc a given operator swings through most gets it first. That is why one segment can be tired while the rest looks new. DYCO-TP-102 — Contact Fatigue, Pitting and Spalling in Planetary Gear Sets →
The duty is the reason it wears
Reversing shock is what punishes a gear train, which is why weak steel shows up here sooner than anywhere else on the machine.
A swing circuit is start, stop, reverse, all day, with a loaded boom’s inertia behind it. On steady-state duty the same weakness would take far longer to show. DYCO-TP-107 — Planet Load Sharing and Carrier Compliance in Epicyclic Travel Drives →
None of this is a rule of thumb: each one is a mechanism, and the publication beside it sets out the engineering it rests on.
Machine down? Start with the number on the tag.
Send the part and your machine to a dealer from here, or email the make and model and we will point you at one who stocks it.