Once your ZPMC gearbox arrives at our facility we disassemble, clean, inspect and measure all gears and shafts and determine if your ZPMC gears and shafts are qualified to be repaired. If the ZPMC gears and shafts are not repairable, we have the capabilities and expertise to manufacture all new ZPMC gears and shafts such as Helical, Double Helical, Herringbone, Split Herring bone, Bevel, Spiral Bevel, Spur Gears, Ring Gears, Eternal Ring Gears, Rack & Pinion, Worm Gears, Double Enveloping Worm Gears, Hypoid Gears, Screw Gears, Plus More! Once your ZPMC gearbox is repaired we then do a six hour test run for overheating, vibration, and leaking to ensure our 24 Month Guarantee. National Gear Box Repair can do all of these repairs and rebuilds at a considerable amount of saving rather than buying a new ZPMC gearbox.