Overview
The ZF 1405.301.021 COMPRESSION SPRING is a precision-engineered OEM genuine component designed to maintain critical clamping force within the shift rail and valve body assemblies of ZF’s WG-series transmissions. This spring ensures that the detent mechanism securely holds the selected gear position, preventing unintended disengagement during operation. The SKU 1405.301.021 is manufactured to ZF’s exacting tolerances, providing consistent load characteristics over extended service intervals. When paired with a properly functioning 5838109012: DIFFERENTIAL, this compression spring helps synchronize load distribution across the drivetrain, reducing wear on adjacent components.
Symptoms of Failure
- Intermittent gear slippage under load – A worn 1405.301.021 spring loses its compressive force, allowing the shift detent to partially release, causing the transmission to pop out of gear during acceleration.
- Hard or imprecise shifting – When the spring fatigues, the shift rail no longer receives consistent pressure, leading to a notchy or vague feel when moving between forward and reverse gears.
- Unusual rattling from the transmission housing – A broken or collapsed spring can allow the shift fork to vibrate against the 5838300626: DIFFERENTIAL HOUSING, producing a metallic chatter at idle or low RPM.
- Delayed engagement when shifting – Reduced spring tension causes the detent plunger to move sluggishly, resulting in a noticeable pause before the transmission fully engages a selected gear.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 1405.301.021 |
| Type | Helical compression spring |
| Wire Diameter | 2.5 mm |
| Outer Diameter | 18.0 mm |
| Free Length | 42.0 mm |
| Material | Chrome-silicon alloy steel (EN 10270-2) |
| Surface Finish | Zinc-phosphate coated |
| Weight | 0.012 kg |
| OEM Reference | ZF 1405.301.021 |
Compatibility
This compression spring is a direct replacement for ZF WG100, WG130, and WG131 transmission models. It also fits select variants of the WG180 and WG200 series where the shift detent assembly shares the same spring pocket dimensions. For optimal performance, always inspect the mating 0750117075: TAPER ROLLER BEARING and the 2093209023: DIFFERENTIAL for wear when replacing the spring, as degraded bearings can accelerate spring fatigue.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 5838109012 | DIFFERENTIAL | Distributes torque between axles |
| 0750117075 | TAPER ROLLER BEARING | Supports axial and radial loads on shafts |
| 2093209023 | DIFFERENTIAL | Manages speed difference between wheels |
| 5838300626 | DIFFERENTIAL HOUSING | Encloses and protects differential gears |
| 0631329088 | SPRING PIN | Secures shift fork to shift rail |
| 5838300811 | THRUST WASHER | Reduces axial friction in gear sets |
| 5838300721 | AXLE BEVEL GEAR | Transfers power to axle shafts |
| 5838300633 | AXLE | Transmits rotational force to wheels |
| 5838300753 | THRUST WASHER | Controls end-play in differential assembly |
| 5838300818 | THRUST WASHER | Provides wear surface for planetary gears |
Frequently Asked Questions
Q: How do I know if the 1405.301.021 spring is the cause of my shifting issues?
A: Measure the free length of the removed spring. If it is shorter than 40 mm or shows visible cracks, replace it immediately. Also check the detent plunger for scoring.
Q: Can I reuse the old spring if it looks intact?
A: ZF does not recommend reusing compression springs. Even if visually intact, the spring may have lost up to 15% of its rated load capacity after 100,000 cycles, leading to premature shift problems.
Q: Does this spring require any special lubrication during installation?
A: Yes. Apply a thin film of ZF-approved transmission assembly grease (Part No. 5010.000.001) to the spring coils and the detent bore to prevent galling during initial operation.
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Email: info@partszf.com |
Phone: +86 158 2286 3467 |
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