Overview
The ZF 4108.303.326 SUN GEAR is a critical planetary component engineered for the WG100, WG130, and WG131 transmission series. As the central input gear within the planetary gearset, it distributes torque from the MOTOR to the planet gears, enabling smooth ratio changes under heavy loads. This OEM genuine part (SKU: 4108.303.326) is precision-machined to maintain exact mesh alignment with the planetary carrier and ring gear, ensuring minimal backlash and maximum power transfer efficiency in your ZF drivetrain.
Symptoms of Failure
- Whining or howling noise during acceleration: Worn sun gear teeth create irregular contact patterns, producing a distinct high-pitched sound that intensifies under load.
- Intermittent gear slipping in forward or reverse: As the sun gear’s splines wear, torque transfer becomes inconsistent, causing the transmission to momentarily lose drive engagement.
- Metallic debris in transmission fluid: Flaking or pitting on the sun gear’s tooth flanks sheds fine metal particles, which can be detected during routine oil changes or filter inspections.
- Hard shifting or delayed engagement: Excessive wear alters the gearset’s preload, forcing the COVER and valve body to compensate with higher hydraulic pressure.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4108.303.326 |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Outer Diameter | 98.4 mm (3.87 in) |
| Inner Spline Diameter | 38.0 mm (1.50 in) |
| Tooth Count | 24 teeth (helical cut) |
| Weight | 0.85 kg (1.87 lbs) |
| OEM Reference | ZF 4108.303.326 |
Compatibility
This sun gear is a direct fit for ZF WG100, WG130, and WG131 transmissions. It also serves as a service replacement for certain variants of the WG180 and WG200 series when used in conjunction with the correct HOUSING and TAPERED ROLLER BEARING. Always verify your transmission’s serial number against the OEM parts catalog to confirm interchangeability.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4108101155 | HOUSING | Encloses the planetary gearset and supports shaft alignment |
| 0501212153 | MOTOR | Hydraulic drive unit that inputs torque to the sun gear |
| 0501314793 | COVER | Seals the transmission housing and retains lubrication |
| 0735370299 | TAPERED ROLLER BEARING | Supports axial and radial loads on the sun gear shaft |
| 0501317874 | HOUSING | Alternate housing variant for WG130 series |
| 0501317875 | ROLLER | Needle roller for planetary pinion support |
| 0501298376 | PISTON | Hydraulic piston for clutch pack engagement |
| 0501317876 | COMPRESSION SPRING | Returns piston to neutral position |
| 0501314823 | BUSH | Wear sleeve for sun gear pilot bore |
| 0501314795 | CAM DISC | Controls shift timing in the valve body |
ZF 4108.303.326 SUN GEAR – Gear RFQ Support
Use ZF 4108.303.326 SUN GEAR as the reference when requesting gear support. Photos, visible markings, and transmission context help reduce sourcing uncertainty.
Part-Number Summary
Use ZF number 4108.303.326 when sending your RFQ. PartsZF can review dotted, spaced, and compact number formats against the available product and documentation records.
Application Context
- Illustration section: OUTPUT
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 | 4108.303.326 |
|---|---|
| Normalized SKU | 4108303326 |
| Part name | SUN GEAR |
| Product category | gear |
| RFQ support | Part-number lookup and documentation review |
| Media support | Product photo or diagram review when available |
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 4661.302.010 GEAR
- 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
