PIV Gearbox Repair and Rebuild

PIV, short for Positively Infinitely Variable, built its name on the all steel link chain variator and grew into heavy industrial gear units for extruders, kneaders, mixers, rolling mills and presses. That equipment is precise and heavily loaded, so it does not forgive worn bearings or starved oil for long. Most of what we see is the same handful of failure patterns: thrust bearing breakdown under screw load, pitting on the gear flanks, shaft and spline wear, and seal leaks that quietly starve the gears of oil. We have built our process around catching all of it before we quote a single part.

Distance is not a problem. We offer free shipping both ways, free pickup and delivery including crating and rigging, and a free inspection before you commit to anything. Whether your PIV unit drives a compounding line, a profile extruder or a process mixer, send it in and we will tell you exactly what is wrong. We document our specialty in extruder gearbox repair too, since that is where most PIV drives live.

PIV equipment is well built, so failures almost always trace back to load, lubrication or time, not to bad design. These are the conditions we find most often on PIV units that come through the shop.

• Thrust bearing collapse. An extruder screw pushes back hard, often more than ten tons of axial load with melt pressures above thirty megapascals. That force lands on the thrust bearing inside the gearbox. When oil film breaks down or the bearing simply wears out, you get heat, metal in the oil, and eventually a seized or destroyed thrust pack. This is the single most common PIV extruder drive failure.
• Tooth flank pitting and spalling. Overload, misalignment and degraded oil cause pitting on the helical and bevel tooth flanks. Left alone it grows into spalling and broken teeth. We inspect every flank for wear pattern and contact before deciding what gets reground and what gets recut.
• Shaft and spline wear. Input and output shafts, splines and coupling bores wear and fret over thousands of running hours, which throws off alignment and feeds back into bearing and gear damage.
• Seal failure and lube starvation. Worn seals leak oil, drop the level, and quietly starve the gears and bearings. By the time the leak is obvious the internal damage is often already done.
• Chain and disc wear on variators. On the chain variators, the link chain and the conical running surfaces wear and pit, which shows up as speed drift, slip and noise under load.

Because so many PIV failures start at the bearings, we treat bearing work as its own discipline. See our bearing repair page.

We are an independent gear repair shop. We are not an authorized PIV dealer and we are not affiliated with the PIV brand or its owners. We name PIV only to describe the equipment we service, and we repair and rebuild these units as an OEM alternative for plants that need them back in service without OEM lead times.

Because we ship free both ways and handle pickup, delivery, crating and rigging at no charge, it does not matter whether your plant is in Houston or across the country. The inspection is free and there is no obligation to proceed. If you want to see the kind of heavy industrial work we do every day, our industries and brands pages cover the rest of the equipment we keep running.

Up to a 24 month workmanship warranty backs every rebuild, which is our way of standing behind the fact that the unit really did leave here right.