The Multiquip 21490 Internal Spur Gear is a genuine OEM component designed for HTX44 and STX55 series hydrostatic ride-on power trowels — including HTX44K4, HTX44K5, HTX44Y4, HTX44Y5, STXD6i, HTXD6i, and STX55Y6 — as well as MQD2H, MQD2HA, MQD3H, and MQD3HA diaphragm pumps. As a direct Multiquip OEM part, 21490 is manufactured to the same specification as the original gear, ensuring proper mesh, load transfer, and dimensional fit without any modification. Sourced directly through authorized supply channels, this part is the dependable choice when a worn or damaged internal spur gear needs to be swapped out quickly and correctly. DHS Equipment stocks Multiquip OEM parts to keep your equipment back in service without the guesswork of fitment uncertainty.
Key Features
- Genuine OEM Gear Geometry — Machined to exact tooth profile and pitch specifications, ensuring correct mesh engagement and load distribution within the gear train.
- Drop-In Compatibility — Matches the original mounting bore, outer diameter, and tooth count for straightforward installation on HTX44K4, HTX44K5, HTX44Y4, HTX44Y5, STXD6i, HTXD6i, STX55Y6, MQD2H, MQD2HA, MQD3H, and MQD3HA units.
- Broad Cross-Equipment Fitment — Covers both the HTX44 and STX55 hydrostatic ride-on trowel families as well as MQD-series diaphragm pumps, making it a versatile stocking part across multiple Multiquip product lines.
- Sustained Drive Train Integrity — A correctly functioning internal spur gear maintains consistent torque transfer; a worn or chipped gear causes vibration, noise, and progressive damage to mating components.
- Authorized Multiquip OEM Part — Supplied through authorized distribution, so the part number 21490 is verified against current Multiquip bill-of-materials records.
An internal spur gear transmits rotational force between shafts inside a gearbox or drive assembly by meshing its inward-facing teeth with a mating pinion or drive gear. In ride-on trowel applications, the gear is part of the blade-pitch or rotor drive system and must maintain precise tooth contact under sustained cyclic load to deliver smooth, consistent blade operation. In diaphragm pump applications, it forms part of the drive mechanism that converts engine rotation into the reciprocating motion needed to move fluid. When an internal spur gear wears, chips, or cracks, the result is audible gear noise, erratic output, and — if left unaddressed — accelerated wear on the surrounding drive components.
Part Details
| Part Number | 21490 |
|---|---|
| Brand | Multiquip |
| Part Type | Genuine OEM |
| Description | Internal Spur Gear |
Compatibility & Fitment
| Name | Model |
|---|---|
| Whiteman Ride-On Power Trowels | HTX44K4 |
| Whiteman Ride-On Power Trowels | HTX44K5 |
| Whiteman Ride-On Power Trowels | HTX44Y4 |
| Whiteman Ride-On Power Trowels | HTX44Y5 |
| Whiteman Ride-On Power Trowels | STXD6i |
| Whiteman Ride-On Power Trowels | HTXD6i |
| Whiteman Ride-On Power Trowels | STX55Y6 |
| Diaphragm Pumps | MQD2H |
| Diaphragm Pumps | MQD3H |
| Diaphragm Pumps | MQD2HA |
| Diaphragm Pumps | MQD3HA |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
