What Information Should Be on a Gearbox Purchase Order?
An industrial gearbox purchase order should contain enough information to make it clear exactly what the plant expects the supplier to deliver.
A PO that says:
1 Gearbox — Model XYZ — $18,500
may be technically sufficient to place an order, but it leaves important details outside the purchasing record.
For a critical industrial gearbox, the purchase order should document the approved:
manufacturer,
complete model and configuration,
ratio,
shafts,
mounting arrangement,
motor interface,
mounting position,
rotation,
accessories,
lubrication requirements,
drawings,
required delivery date and
any agreed modifications.
The objective is simple:
The gearbox described on the purchase order should be the same gearbox maintenance and engineering approved for the machine.
Here is what maintenance buyers should consider including.
Gearbox Purchase Order Checklist
Before releasing a gearbox PO, verify that the purchasing record identifies the following where applicable.
Basic Order Information
Manufacturer
Complete model/configuration number
Supplier quotation number and revision
Quantity
Unit price
Extended price
Ship-to location
Required delivery date
Gearbox Performance
Gear ratio
Input RPM
Required output RPM
Motor horsepower/kW
Required torque/rating where applicable
Application or equipment identification
Mechanical Configuration
Solid or hollow output shaft
Output shaft/bore size
Keyway or connection type
Input arrangement
Motor adapter/frame
Mounting arrangement
Mounting position
Rotation
Backstop and direction
Accessories
Cooling equipment
Breather
Torque arm
Shrink disc or bushing
Coupling components
Sensors
Special seals/coatings
Other required accessories
Documentation and Verification
Approved dimensional drawing/revision
Supplier quote/revision
Required modifications identified
Lubrication requirements
Warranty requirements
Inspection/testing requirements if applicable
The exact PO does not need to reproduce an entire engineering specification.
But it should clearly reference the documents that define the approved gearbox.
1. Put the Manufacturer on the PO
Identify the manufacturer explicitly.
Do not rely solely on a distributor's internal part number.
For example:
Manufacturer: [Manufacturer Name]
This matters when:
multiple brands were quoted,
the supplier offers equivalent products,
the gearbox is being cross-referenced or
purchasing has approved one specific manufacturer.
If substitutions are not allowed after PO placement, state that.
For example:
No manufacturer substitution without written approval.
2. Use the Complete Gearbox Model Number
The PO should include the complete approved model/configuration number.
Avoid shortening the model number.
Gearbox nomenclature may identify:
product family,
housing size,
ratio,
shaft arrangement,
mounting,
motor adapter,
accessories or
other configuration information.
One missing character can matter.
The model number on the PO should match the supplier's final quotation.
3. Reference the Supplier's Quote Number
This is one of the easiest ways to reduce ambiguity.
Include:
Supplier Quote: Q-12345
Better:
Supplier Quote: Q-12345, Revision 3, dated September 8, 2026
The revision is important.
A gearbox quotation may change several times while engineering questions are resolved.
If purchasing references only the original quote number, it may not be obvious which configuration was approved.
Always Reference the Final Quote Revision
Imagine:
Revision 1
Standard output shaft.
Revision 2
Corrected output shaft.
Revision 3
Added backstop and NEMA motor adapter.
Maintenance approves Revision 3.
The PO should reference Revision 3, not simply the general quote number.
4. Include the Quantity
This sounds obvious, but gearbox procurement may involve more than one purpose.
For example:
Quantity: 2
1 for immediate installation + 1 critical spare
That additional description can help explain the order internally.
5. Include the Gear Ratio
Record the approved ratio.
Use the actual quoted ratio where possible.
For example:
Ratio: 25.14:1
rather than:
Approximately 25:1
The difference may matter when maintaining a required machine speed.
See Why Matching the Gear Ratio Isn't Enough When Replacing a Gearbox.
6. Include Input and Output Speed Where Important
If machine speed matters, include:
Input Speed: 1,750 RPM
Nominal Output Speed: 69.6 RPM
The relationship is approximately:
Output RPM = Input RPM ÷ Gear Ratio
Documenting both provides another check against an incorrect configuration.
7. Identify the Application
Include the equipment or asset the gearbox is intended to serve.
For example:
Application: Plant 2 — Conveyor C-17 Head Drive
or:
Asset ID: GBX-042
This helps prevent a gearbox purchased for one machine from being confused with another similar unit.
If your plant maintains a gearbox asset register, use the same asset identification on the purchase order.
8. Include Motor Power Where Appropriate
Record the motor rating associated with the approved selection.
For example:
Motor: 50 HP
or:
Motor: 37 kW
If the motor is being purchased with the gearbox, the PO will require considerably more motor information.
If the existing motor will be reused, state that clearly.
9. State Whether the Existing Motor Must Be Reused
For a motor-mounted gearbox, this is critical.
Include:
Gearbox must accept existing NEMA 256TC motor.
or:
Existing IEC 160 motor to be reused.
The supplier should already have verified compatibility during the RFQ process.
The PO simply preserves that requirement.
See NEMA vs. IEC Motor Adapters on Industrial Gearboxes.
10. Identify the Input Arrangement
State whether the gearbox is:
C-face motor mounted,
IEC motor mounted,
separate coupled,
shaft input or
another configuration.
For example:
Input: NEMA C-face motor adapter for 256TC frame
or:
Input: Solid input shaft for flexible coupling
See C-Face Motor-Mounted Gearboxes vs. Separate-Coupled Gearboxes.
11. Identify the Output-Shaft Configuration
State whether the approved gearbox uses:
solid output shaft,
keyed hollow bore,
shrink disc,
taper bushing,
flange output or
another configuration.
For example:
Output: 3.000-inch keyed solid shaft
or:
Output: 80 mm keyed hollow bore
This is far better than relying on the word:
“standard.”
12. Include Shaft Dimensions When They Are Critical
For a replacement gearbox, consider including critical dimensions directly on the PO or through an approved drawing reference.
Examples:
Output Shaft Diameter: 3.000 in.
Output Shaft Extension: 6.50 in.
Keyway: 3/4 in.
For a hollow shaft:
Hollow Bore: 80 mm
Connection: Keyed
See Hollow-Shaft vs. Solid-Shaft Gearbox Replacement.
13. Identify the Hollow-Shaft Connection System
“Hollow shaft” alone may not be sufficient.
State whether the connection uses:
key,
shrink disc,
taper bushing or
another arrangement.
See Keyed Hollow Bore vs. Shrink Disc vs. Taper Bushing.
If a shrink disc or bushing is supposed to ship with the gearbox, say so explicitly.
14. Include the Mounting Arrangement
Specify:
foot mounted,
flange mounted,
shaft mounted,
torque-arm mounted or
another approved arrangement.
This should agree with the final drawing.
15. Include Critical Mounting Dimensions—or Reference the Drawing
For a replacement, the important dimensions may include:
bolt pattern,
center height,
shaft location,
flange dimensions and
overall envelope.
You do not necessarily need every dimension typed into the PO.
A cleaner method is:
Dimensions shall conform to approved drawing DWG-12345 Rev. B.
That makes the drawing part of the purchasing definition.
See Gearbox Replacement Dimensions: The Measurements That Determine Whether a Reducer Will Fit.
16. Reference the Approved Dimensional Drawing
This may be the most important documentation step for a critical replacement.
If the supplier provided a drawing and maintenance/engineering approved it, include:
Approved Drawing: ABC-123456 Rev. B
Do not simply write:
“Per drawing.”
Identify the drawing and revision.
Why the Drawing Revision Matters
Suppose the supplier changes:
output shaft,
motor adapter,
mounting feet or
accessory location
between drawing revisions.
If the PO references the wrong revision, the purchasing record becomes ambiguous.
The same revision-control discipline used for the quotation should be used for drawings.
17. State the Mounting Position
Include the approved mounting position.
But if the replacement is from another manufacturer, make sure the code corresponds to that manufacturer's actual configuration.
Do not simply transfer an old code such as:
M1, M2, M3, M4, M5, or M6
without confirming what it means for the proposed gearbox.
See Understanding Gearbox Mounting Position Codes When Changing Manufacturers.
18. Specify Rotation Where Necessary
If output rotation is important, state it.
This becomes particularly important when:
a backstop is used,
the machine cannot reverse or
the gearbox arrangement changes direction.
Use an unambiguous reference point.
For example:
Output shaft clockwise when viewed from output-shaft end.
Avoid simply writing:
CW
without saying from which direction it is viewed.
19. Specify the Backstop
If a backstop is required, put it on the PO.
For example:
Backstop: Required
Permitted Output Rotation: Clockwise when viewed from output shaft
The supplier quote should identify the corresponding backstop configuration.
20. Identify Cooling Requirements
If the approved gearbox includes:
shaft-mounted fan,
electric fan,
oil pump,
oil-to-air cooler,
oil-to-water cooler or
another cooling system,
list it or reference it through the approved configuration.
Cooling should not disappear between quotation and PO.
21. Identify the Breather
For some applications, the breather may be a specific requirement.
Examples might include:
standard breather,
desiccant breather,
remote breather arrangement or
special environmental protection.
If the application requires something beyond the manufacturer's standard configuration, document it.
22. Include Required Sensors
If the approved gearbox includes instrumentation, list it.
Examples:
bearing RTDs,
oil-temperature sensor,
vibration sensors,
oil-level switch,
pressure switch or
flow switch.
For each critical sensor, purchasing should know whether it is:
supplied installed,
supplied loose or
provided by the plant.
23. Include Special Seals or Coatings
If the environment requires:
special shaft seals,
corrosion-resistant coating,
washdown protection,
food-industry coating or
another special configuration,
include it on the order.
Do not assume the supplier will infer the environment from the plant name.
24. Identify the Torque Arm
For a shaft-mounted gearbox, state whether the torque arm is:
included,
reused from the existing installation or
supplied separately.
If the new gearbox requires a different torque arm, make sure it is part of the order.
25. Identify the Coupling Scope
For separate-coupled drives, specify whether the order includes:
complete coupling,
gearbox-side hub,
motor-side hub,
spacer,
hardware or
no coupling components.
For example:
Include gearbox-side coupling hub bored and keyed for quoted input shaft.
This avoids a gearbox arriving without the component needed to connect it.
26. Identify Adapter Plates or Mounting Modifications
If the approved replacement requires an adapter plate, include it explicitly.
For example:
Adapter Plate: Included per AP-102 Rev. A
or:
Adapter Plate: To be fabricated by customer; supplier to provide mounting dimensions.
See When a Gearbox Interchange Requires an Adapter Plate—and When It Doesn't.
27. Identify What Is NOT Included
Sometimes exclusion is as important as inclusion.
For example:
Motor not included — existing motor will be reused.
Coupling not included — existing coupling retained.
Lubricant not included — customer supplied.
This helps maintenance plan the installation.
28. State the Lubrication Requirements
The PO should make clear whether the gearbox will ship:
filled with oil,
with oil supplied separately or
without lubricant.
For example:
Ship filled with manufacturer-recommended lubricant for specified mounting position where permitted.
or:
Gearbox ships dry. Supplier shall provide required lubricant specification and fill quantity before shipment.
Do not assume a gearbox contains oil when it arrives.
29. Confirm the Mounting Position and Oil Quantity Together
Lubricant quantity can depend on mounting position.
Therefore, the approved configuration should establish both.
If the gearbox is changed from horizontal to vertical, the correct oil quantity and lubrication arrangement may change.
30. Specify Documentation Required With Shipment
Depending on the application, request:
installation manual,
operation and maintenance manual,
lubrication instructions,
certified dimensional drawing,
parts list,
recommended spare parts,
test documentation and
warranty information.
These documents become valuable years later when the gearbox needs service.
31. Request the Final Certified Drawing When Appropriate
For important equipment, consider requiring:
Final certified/as-built dimensional drawing to be supplied with documentation.
This can then be added to the plant's asset register.
The next replacement becomes much easier.
32. Specify Testing or Inspection Requirements
Most standard replacement gearboxes will not require unusual customer inspection requirements.
For large or highly critical drives, however, the PO may need to identify:
factory testing,
vibration testing,
temperature testing,
inspection hold points,
documentation requirements or
customer witness testing.
These requirements should be agreed during quotation—not added unexpectedly after the PO.
33. State the Required Delivery Date
The PO should contain an actual required date.
For example:
Required On Site: October 12, 2026
This is more useful than:
ASAP
or:
Rush.
Required Date vs. Supplier Ship Date
These are different.
If the gearbox must be on site October 12, a supplier shipping it October 12 may already be late.
Where the distinction matters, document both:
Supplier Confirmed Ship Date: October 8
Required On-Site Date: October 12
34. Preserve the Quoted Lead-Time Commitment
If the supplier's quotation says:
Ships 3–4 weeks ARO
and delivery is critical, purchasing should obtain a confirmed expected ship date when the PO is acknowledged.
See Gearbox Lead Times Explained: Stocked vs. Assembled vs. Modified vs. Custom Units.
35. Request Order Acknowledgment
For critical gearbox orders, require acknowledgment.
Then compare the acknowledgment against the PO.
Verify:
manufacturer,
model,
quantity,
price,
configuration,
drawing revision and
ship date.
Do not assume the supplier's order-entry system interpreted every PO note correctly.
The PO Isn't Finished When You Send It
For critical equipment, the process should be:
PO Issued → Supplier Acknowledgment Received → Acknowledgment Checked → Discrepancies Resolved
That final check can catch errors before manufacturing or modification begins.
36. Control Substitutions
If purchasing has approved a specific gearbox, consider language such as:
No substitutions, configuration changes, or deviations from referenced quotation/drawing without written purchaser approval.
This is particularly useful when interchangeability has already been technically reviewed.
See What Makes Two Industrial Gearboxes Truly Interchangeable?.
37. Don't Copy an Old PO Without Rechecking It
An old purchase order can be a valuable reference.
It can also perpetuate an old mistake.
Before copying a previous PO, confirm:
manufacturer,
model,
configuration,
revision,
shaft dimensions,
accessories and
application.
The installed gearbox may have changed since the old PO was issued.
38. Don't Let Purchasing Notes Override the Approved Quote Accidentally
Suppose the supplier's approved quotation says:
Ratio: 24.87:1
but an old purchasing description says:
25:1 gearbox.
Now the PO contains conflicting information.
Resolve the conflict before issuing the order.
The PO, quote, and approved drawing should tell the same story.
The Three-Document Rule
For a critical replacement, three documents should align:
1. Purchase Order
What purchasing is ordering.
2. Supplier Quotation
What the supplier offered.
3. Approved Drawing
What maintenance/engineering verified.
Ideally:
PO = Quote = Drawing
If those three documents describe different configurations, stop and resolve the discrepancy.
39. Use Revision Control
A simple revision table can prevent expensive mistakes.
DocumentReferenceRevisionSupplier QuoteQ-12345Rev. 3Dimensional DrawingDWG-67890Rev. BAdapter Plate DrawingAP-102Rev. APlant SpecificationGBX-042Rev. 2
Include the applicable references on the PO.
40. Include the Plant Asset Number
If your facility uses asset numbers, include one.
For example:
Plant Asset: GBX-042
Equipment: Conveyor C-17 Head Drive
This creates a traceable connection between:
Machine → Gearbox → Drawing → Purchase Order → Supplier
That information becomes extremely useful years later.
41. Preserve the Information After Installation
Once the gearbox is installed, update the gearbox asset register with:
new manufacturer,
model,
serial number,
ratio,
purchase order,
supplier,
installation date,
drawing,
lubricant,
motor information and
replacement/spare information.
Do not let the knowledge disappear into an old purchasing file.
42. Update the Spare Strategy
If the new gearbox replaces an obsolete model, ask:
Should this become the plant's approved replacement for other identical machines?
If yes, update:
spare records,
cross-reference lists,
asset register,
procurement specifications and
maintenance documentation.
This supports gearbox standardization across the manufacturing plant.
A Sample Industrial Gearbox Purchase Order Description
A stronger PO line-item description might look like this:
Industrial Gear Reducer — Qty. 1
Manufacturer: [Manufacturer]
Model/Configuration: [Complete Model]
Ratio: 25.14:1
Input Speed: 1,750 RPM
Application: Conveyor C-17 Head Drive / Asset GBX-042
Input: NEMA C-face adapter for existing 50 HP, 256TC motor
Output: 3.000-in. keyed solid shaft
Mounting: Foot mounted
Mounting Position: [Approved Manufacturer Position]
Backstop: Required; output rotation CW viewed from output-shaft end
Cooling: Shaft-mounted fan
Lubrication: [Requirement]
Adapter Plate: Included per AP-102 Rev. AFurnish in accordance with Supplier Quote Q-12345 Rev. 3 and approved dimensional drawing DWG-67890 Rev. B.
No substitutions or configuration changes without written approval.
Required on site: October 12, 2026.
Provide installation/maintenance manual, lubrication requirements, final dimensional drawing, and warranty documentation with shipment.
That description gives purchasing, maintenance, receiving, and the supplier a common reference.
Purchase Order Information vs. RFQ Information
The two documents serve different purposes.
The RFQ Asks:
What solution can you provide?
It may contain:
existing gearbox information,
photographs,
application,
measurements,
motor data,
required delivery and
acceptable alternatives.
See Industrial Gearbox Procurement Checklist: What to Send With an RFQ.
The Purchase Order Says:
This is the solution we approved and are ordering.
It should preserve the final:
manufacturer,
model,
configuration,
quote revision,
drawing revision,
accessories,
scope and
delivery commitment.
That distinction matters.
The RFQ Can Contain Options; the PO Should Remove Ambiguity
During the RFQ stage, you may be evaluating:
Option A
Original manufacturer.
Option B
Cross-brand drop-in.
Option C
Stocked gearbox with adapter plate.
Option D
Repair existing gearbox.
Once the decision is made, the PO should identify exactly which option was selected.
The supplier should not have to infer the answer from an old email chain.
Avoid Ordering the Wrong Gear Reducer
Before issuing the PO, use the process described in How Maintenance Buyers Can Avoid Ordering the Wrong Gear Reducer.
At minimum, confirm:
Correct Gearbox → Correct Configuration → Correct Drawing → Correct Accessories → Correct Delivery
If any one of those remains uncertain, resolve it before the order becomes difficult or expensive to change.
Receiving Should Have Enough Information to Check the Shipment
A good PO can also improve receiving inspection.
When the gearbox arrives, receiving or maintenance can compare:
manufacturer,
model,
serial information,
visible shaft configuration,
motor adapter,
backstop,
accessories and
documentation
against the order.
For critical gearboxes, consider photographing the unit immediately after uncrating.
If something is wrong, identify it before installation day.
The Cost of a Clear Gearbox PO Is Almost Zero
Adding:
a quote revision,
drawing number,
shaft description,
motor frame,
backstop requirement and
delivery date
may take only a few minutes.
The cost of omitting them can include:
return freight,
restocking charges,
rework,
emergency machining,
expedited freight,
installation delays and
additional production downtime.
That makes PO accuracy one of the least expensive forms of gearbox risk reduction.
What Information Should Be on a Gearbox Purchase Order?
The exact requirements vary by application, but a strong industrial gearbox purchase order should answer:
Who made it?
Exactly which gearbox are we ordering?
What approved configuration are we buying?
What machine is it for?
How does it connect to the motor and driven equipment?
How is it mounted?
What accessories are included?
Which quote and drawing define it?
What modifications are included or excluded?
When must it ship and arrive?
If those answers are clear, the risk of an ordering misunderstanding drops significantly.
Need Help Before Issuing a Gearbox Purchase Order?
Industrial Gearbox Supply can help maintenance and purchasing teams verify industrial gearbox replacement options before an order is released.
For replacement applications, provide:
existing gearbox manufacturer,
model and serial number,
gearbox nameplate photo,
motor nameplate photo,
application,
installation photographs,
shaft dimensions,
mounting dimensions,
proposed replacement information and
required delivery date.
For cross-brand replacements, obsolete gearboxes, and modified installations, reviewing the dimensional and configuration details before the PO can help prevent costly surprises when the gearbox arrives.
The RFQ finds the solution. The purchase order should define exactly what you're buying.
Sources
American Gear Manufacturers Association (AGMA)
Technical standards and resources for enclosed industrial gear drives, rating, design, application, lubrication, and related engineering considerations.
https://www.agma.org/
SEW-EURODRIVE — Industrial Gear Units
Industrial gearbox product and engineering information covering mounting configurations, motor interfaces, accessories, lubrication, and drive selection.
https://www.sew-eurodrive.com/products/gear_units/industrial_gear_units/industrial_gear_units.html
NORD DRIVESYSTEMS — Industrial Gear Units
Industrial gearbox resources covering shaft arrangements, mounting positions, motor adapters, cooling options, and configuration information.
https://www.nord.com/en/products/industrial-gear-units/industrial-gear-units.jsp
Sumitomo Drive Technologies — Products
Manufacturer information covering industrial reducers, gearmotors, shaft configurations, and power-transmission solutions.
https://us.sumitomodrive.com/en-us/products
Regal Rexnord — Falk
Manufacturer information covering Falk industrial gear drives and related mechanical power-transmission equipment.
https://www.regalrexnord.com/brands/falk