At Specialty Gear Drives, we specialize in the emergency repair, rebuild, and in-house manufacturing of Zambello extruder gearboxes — single screw, co-rotating twin screw, counter-rotating parallel, conical twin, and injection molding drive configurations. Italian-precision engineering restored to better-than-OEM condition, fast.
All Fields Must Be Filled Out
Founded in Italy in 1957 as a family business by Zevio Zambello, the Zambello Group began producing precision helical gearboxes for the local industrial sector. Over the following decades, Zambello became the worldwide standard in extruder drive technology — particularly for plastics processing — through a philosophy of non-standard, modular gearboxes engineered precisely to customer application requirements. Every Zambello component including casings and toothed wheels is produced in-house and verified with advanced CNC measuring systems. When this level of precision fails in your facility, Specialty Gear Drives is the team that can restore it.
Full Zambello Product Range
Zambello produces a comprehensive range of extruder drives. We service all configurations — modular, non-standard, and custom-built units — across the entire Zambello catalog.
Zambello's core single screw extruder drive — the workhorse of plastics processing lines worldwide. We restore all helical gear profiles, shafts, and bearings to OEM dimensional and surface finish specifications.
High-torque co-rotating twin screw drive gearboxes for compounding, blending, and reactive extrusion. These complex multi-shaft configurations require specialist knowledge our team brings to every repair.
Counter-rotating parallel twin configurations for PVC and specialty compound processing. We service the complete internal assembly including all counter-shaft, distribution gear, and output shaft components.
Conical twin screw extruder gearboxes for profile and pipe extrusion. The converging geometry of these drives requires precision shaft alignment and bearing preload work performed by our specialist technicians.
Zambello gearboxes for injection molding machine plasticizing and injection units. We repair both the drive gearbox and associated speed/torque multiplication stages to full OEM specification.
Zambello's philosophy of non-standard, customer-specific modular gearboxes means many units are unique configurations. Our reverse engineering capability ensures we can restore any Zambello gearbox regardless of standard parts availability.
The Extruder Gearbox Standard — Restored Fast
In plastics extrusion, downtime is production loss measured by the hour. Zambello gearboxes are the go-to drive solution for plastics processing worldwide — and when one fails, you need a repair partner who understands extrusion applications as thoroughly as the gearbox itself.
We carry critical spare parts for Zambello gearboxes in stock and manufacture replacement components in-house when standard stock is insufficient — eliminating the overseas lead times that would otherwise add days or weeks to your repair. Our technicians are familiar with the full Zambello product range across all extrusion configurations.
Root Cause Analysis
Zambello extruder gearboxes operate under the most demanding conditions in plastics processing — high torque, continuous duty, and exposure to process polymer. We identify the exact root cause before any repair begins.
Process melt migration through worn input shaft seals introduces abrasive polymer residue into the gear oil — attacking gear teeth, bearing surfaces, and shaft journals throughout the drivetrain.
Sustained high-torque extrusion loads cause surface fatigue on Zambello helical gear profiles. Pitting and spalling progress rapidly once initiated, requiring immediate expert intervention.
Axial forces from screw pressure in extrusion applications place extreme demands on thrust bearings. We replace all bearings with Timken-certified equivalents installed via our liquid nitrogen thermal process.
Continuous-duty extrusion cycles combined with inadequate lubrication intervals cause thermal buildup that degrades gear mesh geometry and accelerates seal and bearing failure rates.
High screw torque and misalignment in extrusion line setups cause output shaft fretting, keyway damage, and journal wear in Zambello units requiring precision reconditioning or new shaft manufacture.
Bearing migration under sustained thrust load causes housing bore deterioration in Zambello units. Precision line-boring in our shop restores all critical diameters to OEM tolerances.
Worn input and output shaft seals are the primary entry point for polymer contamination and the primary exit for lubricant. Seal integrity is critical to Zambello gearbox longevity in all extrusion applications.
In co-rotating and counter-rotating configurations, worn distribution gears cause timing errors between screws — triggering contact between rotating elements and requiring immediate disassembly and rebuild.
In-House Manufacturing Capabilities
When a Zambello gear, shaft, or distribution component is beyond repair, we produce a precision replacement on-site matching OEM hardness ratings and tolerances.
Our Proven Method
Every Zambello gearbox receives our full documented rebuild — from initial teardown through final load test and 24-month warranty certification.
We arrange no-cost freight pickup anywhere in the US. Your Zambello unit is logged immediately and assigned to a technician experienced with extruder gearbox configurations.
All components are decontaminated in our industrial parts washer — removing polymer residue, grease, and grime. Every gear, shaft, bearing, and housing bore is individually measured against Zambello OEM tolerances.
We identify and document the exact failure cause — polymer ingress, overloading, misalignment, or lubrication issues — so the same failure doesn't recur when the gearbox returns to your extrusion line.
Worn Zambello gears and shafts are manufactured on-site to original specifications. Helical profiles, distribution gears, and thrust collars all produced in our CNC gear cutting center — no dependence on Italian OEM supply lead times.
Reassembly uses Timken-certified bearings installed via liquid nitrogen thermal process. All new seals, gaskets, and a high-temp polymer housing coating complete the rebuild to better-than-OEM standard.
Every rebuilt Zambello gearbox completes a full six-hour load test monitoring vibration, temperature, and leak-tightness before shipping with our 24-month production warranty.
The Specialty Gear Drives Promise
We manufacture Zambello gears on-site — including Cyclo-series profiles. No OEM backorders slowing your repair down.
Pickup and delivery at zero cost anywhere in the US. We handle all logistics so you focus on getting back online.
Every Zambello rebuild is covered from the moment it returns to production — the strongest guarantee available.
A precision rebuild from Specialty Gear Drives costs a fraction of a new Zambello unit, with equal or better performance.
Our technicians carry the same certifications required by OEM service centers — applied to every Zambello gearbox that enters our shop, from compact Cyclo units to large-frame Paramax drives.
We never press bearings. Thermal shaft shrinkage and a superheated bearing dropped into place creates a perfect interference fit without stress — matching or exceeding Zambello's own installation standards.
Zambello drives are used in critical applications where every hour of downtime has a price tag. Our emergency team is on call around the clock to expedite any repair when production is at risk.
Our repair coordinators — all experienced former gearbox technicians — can often diagnose your Zambello failure over the phone before it ships, saving you critical hours in the repair timeline.
Don’t let a failed Zambello extruder drive halt your plastics production. Call Specialty Gear Drives for a free quote, free pickup, and the fastest certified Zambello repair turnaround available.