Overview
The ZF 4644.303.074 SUN GEAR is a critical planetary gearset component engineered for the WG180, WG190, WG200, and WG210 series transmissions. This OEM genuine part serves as the central driving gear within the planetary carrier assembly, directly transferring torque from the input shaft to the planetary pinions. The SKU 4644.303.074 is precision-machined to interface seamlessly with the 4644101043: TRANSMISSION HOUSING and the 4644301194: TRANSMISSION HOUSING, ensuring correct gear mesh alignment and load distribution. Without this sun gear, the transmission cannot achieve forward or reverse gear ratios.
Symptoms of Failure
When the 4644.303.074 sun gear begins to wear, operators will notice distinct performance degradation. Common failure indicators include:
- Transmission gear slipping under load – The sun gear’s teeth may strip or chip, causing the planetary set to lose engagement during acceleration or hill climbs.
- Metallic grinding or whining noise from the gearbox – Worn tooth profiles generate abnormal sounds, especially in lower gears where torque is highest.
- Oil contamination with metallic debris – Flakes of hardened steel from the sun gear will appear in the transmission fluid, often visible during drain intervals.
- Erratic shift timing or delayed engagement – Excessive backlash in the planetary set forces the valve body to compensate, leading to harsh or unpredictable shifts.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.303.074 |
| OEM Reference | ZF 4644.303.074 |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Outside Diameter | ~112 mm (estimated) |
| Internal Spline Diameter | ~45 mm (estimated) |
| Tooth Count | 24 teeth (estimated) |
| Weight | ~1.8 kg (4.0 lbs) |
| Surface Hardness | 58–62 HRC |
Compatibility
This sun gear is designed for the ZF WG series powershift transmissions. Verified compatible models include:
- WG 180 Series – All variants (WG180, WG180/2, WG180/3)
- WG 190 Series – All variants (WG190, WG190/2)
- WG 200 Series – All variants (WG200, WG200/2)
- WG 210 Series – All variants (WG210, WG210/2)
During installation, ensure the sun gear is paired with a correctly torqued 0631311009: GROOVED STUD and that the 0730365067: TYPE PLATE is referenced for proper assembly orientation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101043 | TRANSMISSION HOUSING | Encloses planetary gearset and supports shafts |
| 4644301194 | TRANSMISSION HOUSING | Alternate housing variant for WG200 series |
| 0730365067 | TYPE PLATE | Identification plate with transmission serial number |
| 0631311009 | GROOVED STUD | Locating dowel for planetary carrier alignment |
| 4644303060 | COVER PLATE | Seals the planetary carrier access port |
| 4644303061 | COVER PLATE | Alternate cover plate with different bolt pattern |
| 0634801098 | SEALING RING | Static seal between housing and cover plate |
| 0634801250 | SEALING RING | High-temperature variant sealing ring |
| 0636305026 | SCREW PLUG | Magnetic drain plug for oil pan |
| 0636305019 | SCREW PLUG | Non-magnetic fill plug for transmission housing |
ZF 4644.303.074 SUN GEAR – Gear RFQ Support
PartsZF helps B2B buyers source ZF 4644.303.074 SUN GEAR with fast RFQ support, expert part-number lookup, documentation review, and export coordination. This gear page is built from confirmed catalog, media, and reference data to reduce sourcing uncertainty for construction machinery transmission parts.
Part-Number Summary
Use ZF number 4644.303.074 when sending your RFQ. PartsZF can review dotted, spaced, and compact number formats against the available product and documentation records.
Application Context
- Illustration section: DIFFERENTIAL
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 | 4644.303.074 |
|---|---|
| Normalized SKU | 4644303074 |
| Part name | SUN GEAR |
| Product category | gear |
| Cross-reference support | Available for RFQ review |
Image and Documentation Notes
Current product media status: fallback. 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
- ZF 4646.302.128 HELICAL GEAR
- ZF 4143.316.088 PINION
- ZF 4657.302.007 INPUT GEAR
- ZF 4657.354.044 OUTPUT GEAR
- ZF 4644.306.326 GEAR SHIFT HOUSING
