Field checklist
What to capture before replacing an industrial gearbox
The fastest replacement quote is usually the one that arrives with enough information to eliminate follow-up questions. This checklist is designed for maintenance, purchasing, and engineering teams standing in front of the installed unit.
1. Nameplate & configurationCapture before removal
01Manufacturer
Record the name exactly. A brand name can also appear on a motor, brake, or machine even when the reducer itself is from another manufacturer.
02Complete model / type
Copy every letter, number, dash, slash, and suffix. Suffixes often encode mounting, output, motor adapter, or option details.
03Serial / order / build number
Capture this separately from the model. Manufacturers can use it to recover the factory configuration when the visible model code is incomplete.
04Ratio (i)
Look for i, ratio, or a value such as 20.0. If the ratio is missing, record both input and output rpm if available.
05Input and output speed
Motor nominal rpm is not always actual operating speed. Note VFD operating range if speed varies.
06Motor power and electrical data
Capture hp or kW, voltage, frequency, phase, motor frame, service factor, brake voltage, and encoder information when present.
07Mounting position
Photograph the installed orientation. Mounting position can affect lubrication quantity, breather location, bearings, and which assembly codes are valid.
08Output connection
Measure solid shaft or hollow-bore diameter, key width/depth, spline, shrink disc, taper bushing, or keyed bushing. Record which side is used.
09Mounting geometry
Measure foot pattern, flange pilot and bolt circle, shaft center height, output offset, torque-arm location, and nearby clearance.
10Application load
Document driven equipment, estimated continuous/peak torque if known, starts per hour, reversing, shock load, and hours/day.
11Environment
Note ambient temperature, washdown, food-grade requirements, dust/water exposure, corrosive atmosphere, outdoor use, and hazardous-area classification.
12Lubrication
Record lubricant type/viscosity if known, fill position, sight glass, breather, drain location, and whether the existing unit has an external cooling or lubrication system.
2. Photos worth taking8 views
- Straight-on photo of the complete nameplate
- Entire gearbox from the output-shaft side
- Entire gearbox from the motor/input side
- Mounting feet or flange with bolt pattern visible
- Output shaft, hollow bore, shrink disc, bushing, or coupling
- Motor nameplate and brake/encoder labels
- Oil sight glass, breather, fill and drain locations
- Wide photo showing the driven machine and available clearance
Use a scale. If drawings are unavailable, include a tape measure, ruler, or caliper in dimensional photos. A perspective photo by itself is poor dimensional evidence.
3. Minimum dimensional checkDo not skip for “same size” units
4. What not to assumeCommon replacement mistakes
Same ratio ≠ same gearbox.
Torque rating, service factor, shaft geometry, bearings, mounting, efficiency, backlash, and thermal capacity can still differ.
Same housing number ≠ drop-in interchange.
Manufacturers can reuse nominal size designations while shaft, flange, centerline, or accessory dimensions differ.
A successor family ≠ a one-to-one successor model.
Manufacturer product transitions often describe a family migration. Exact configuration still needs to be selected.
Motor horsepower alone is not a gearbox rating.
The reducer must handle the actual output torque, duty cycle, shock load, thermal load, and application service.
5. Turn the field data into a searchNext step