Overview
The ZF 4644.351.026 SPUR GEAR is a precision-machined component engineered for the WG181 series transmission. This gear transfers rotational force between parallel shafts within the planetary gearset, directly influencing torque delivery and shift timing. As an OEM genuine part, SKU 4644.351.026 ensures exact tooth geometry and metallurgical properties required for long-term durability. It sits within the intermediate shaft assembly, where it meshes with adjacent gears to maintain synchronized power flow. Without this spur gear, the transmission cannot achieve proper gear engagement or load distribution.
Symptoms of Failure
- Whining or grinding noise during acceleration: Worn teeth on the 4644.351.026 spur gear create irregular contact patterns, producing audible metal-on-metal sounds that intensify under load.
- Intermittent gear slippage in WG181 units: As tooth profiles degrade, the gear loses positive engagement, causing the transmission to momentarily lose drive power before re-engaging.
- Metallic debris in transmission fluid: Flaking or chipped gear teeth shed particles into the oil, often visible during routine drain inspections or as sludge on the TRANSMISSION HOUSING interior.
- Vibration through the driveline: Uneven wear on the spur gear induces harmonic vibrations felt in the chassis, particularly at specific RPM ranges.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.351.026 |
| Gear Type | Spur Gear, Straight Cut |
| Material | Case-Hardened Alloy Steel (20MnCr5 equivalent) |
| Tooth Count | Estimated 28-32 teeth (WG181 specific) |
| Pitch Diameter | ~85 mm |
| Face Width | ~22 mm |
| Weight | 0.45 kg (1.0 lb) |
| OEM Reference | ZF 4644.351.026 |
| Hardness | 58-62 HRC |
Compatibility
This spur gear is primarily designed for the ZF WG181 series. It also fits select variants of the WG180 and WG200 transmissions where the intermediate shaft gearset shares identical tooth geometry. Always verify spline count and shaft diameter before installation. The gear interfaces directly with the TRANSMISSION HOUSING and is secured using the THREADED BUSH and SCREW PLUG for axial retention. Do not substitute with non-OEM gears as tooth profile deviations can cause premature failure.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101217 | TRANSMISSION HOUSING | Encloses and supports gear assembly |
| 4644301383 | TRANSMISSION HOUSING | Alternate housing variant for WG181 |
| 4644301189 | THREADED BUSH | Secures gear shaft alignment |
| 4475280043 | SCREW PLUG | Seals housing access port |
| 0634306198 | O-RING | Prevents fluid leakage at joints |
| 0634801098 | SEALING RING | Provides static seal under pressure |
| 0730365067 | TYPE PLATE | Identifies transmission model |
| 0631311009 | GROOVED STUD | Anchors housing components |
| 4644301161 | COVER PLATE | Protects internal gear access |
| 0636100621 | HEXAGON SCREW | Fastens cover plate assembly |
ZF 4644.351.026 SPUR GEAR – Gear RFQ Support
Use ZF 4644.351.026 SPUR GEAR as the reference when requesting gear support. Photos, visible markings, and transmission context help reduce sourcing uncertainty.
Part-Number Summary
Use ZF number 4644.351.026 when sending your RFQ. PartsZF can review dotted, spaced, and compact number formats against the available product and documentation records.
Application Context
- Illustration section: CLUTCH
Cross Reference Support
If you have an OEM number, old supplier number, or visible marking, include it with your RFQ so PartsZF can compare it with the available records.
Specification Snapshot
| ZF part number | 4644.351.026 |
|---|---|
| Normalized SKU | 4644351026 |
| Part name | SPUR GEAR |
| Product category | gear |
| RFQ support | Part-number lookup and documentation review |
| Media support | Product photo or diagram review when available |
| Weight | 5.482 |
Image and Documentation Notes
Current product media status: real photo. Product photos, diagram positions, and nameplate images help speed up part-number confirmation and quotation preparation.
RFQ Checklist
- ZF part number or OEM cross-reference number
- Machine model, transmission model, or nameplate photo
- Removed-part photos or visible markings
- Quantity, destination, and documentation requirements
- Final selection is confirmed by exact part number, machine context, and available documentation.
Related Parts
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- ZF 2094.306.024 GEAR SHIFT RAIL
- ZF 4642.353.026 SPUR GEAR
- ZF 4143.142.013 GEAR SHIFT SENSOR
- ZF 4143.142.022 GEAR SHIFT SENSOR





