Overview
This OEM genuine ZF 4657.026.020 is a critical internal component engineered specifically for the WG 190 Series transmission. It functions as a precision-machined guide or spacer element within the planetary gearset assembly, ensuring correct axial alignment and load distribution during high-torque operations. The SKU 4657.026.020 is manufactured to ZF’s exacting tolerances to maintain hydraulic pressure integrity and gear mesh accuracy. When installed alongside the 4657101034: TRANSMISSION HOUSING, it forms a sealed, stable environment for the rotating clutch packs and shafts.
Symptoms of Failure
- Erratic gear engagement and delayed shifts – A worn 4657.026.020 can cause axial play, leading to “ZF WG190 slipping under load” and inconsistent clutch application.
- Metallic debris in transmission fluid – Surface fatigue on this part generates fine metal particles, often flagged during “transmission fluid analysis for metal contamination” inspections.
- Low hydraulic pressure warnings – Misalignment from a degraded component disrupts oil flow paths, triggering “WG190 low line pressure” fault codes.
- Abnormal whining or grinding noises – When the part loses its dimensional stability, it produces a distinct “ZF transmission whine in 3rd gear” sound during acceleration.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 4657.026.020 |
| OEM Reference | ZF 4657.026.020 (Genuine) |
| Material | Case-hardened alloy steel |
| Outer Diameter | 98.5 mm |
| Inner Diameter | 42.0 mm |
| Thickness | 12.7 mm |
| Weight | 0.34 kg |
| Surface Treatment | Phosphate coating for corrosion resistance |
Compatibility
This OEM part is designed for the ZF WG 190 Series, including the WG180, WG190, and WG200 models. It is also used in select ZF 4WG-190 and 5WG-190 variants. The 4657.026.020 interfaces directly with the 4657201027: HOUS.FRONT SECT and the 4657201012: HOUSING REAR PART to create the main structural cavity. Proper installation also requires the 0631306792: CYLINDRICAL PIN for precise dowel alignment during assembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657101034 | TRANSMISSION HOUSING | Main structural casing for gearset and valve body |
| 4657201027 | HOUS.FRONT SECT | Front section housing the torque converter and pump |
| 4657201012 | HOUSING REAR PART | Rear section supporting output shaft and PTO |
| 0631306792 | CYLINDRICAL PIN | Dowel pin for precise alignment of housing halves |
| 0636100801 | CAP SCREW | M10 fastener for securing housing sections |
| 4656301148 | FIXING PLATE | Locking plate for clutch piston retention |
| 4657301032 | SCREEN SHEET | Fine mesh filter for oil return circuit |
| 4657301033 | SCREEN SHEET | Coarse mesh pre-filter for suction line |
| 0636100803 | CAP SCREW | M8 bolt for valve body attachment |
| 4681301040 | OIL FEED.HOUSG. | Pressurized oil distribution manifold |
Frequently Asked Questions
Q: Can I reuse the 4657.026.020 if it shows minor wear?
A: No. ZF specifies that this part must be replaced whenever the transmission is overhauled. Even superficial wear can alter clutch pack clearances and cause premature failure of the TRANSMISSION HOUSING.
Q: Does this part require special tools for installation?
A: Yes. You will need a bearing press and a dial indicator to verify runout after installing the CYLINDRICAL PIN. Always torque the CAP SCREW fasteners to factory specifications.
Q: Is the 4657.026.020 interchangeable between WG180 and WG200 models?
A: Yes. This part number is shared across the WG180, WG190, and WG200 families. However, always verify the HOUSING REAR PART compatibility if retrofitting from a different series.
📞 Need this part? Contact our ZF specialists:
Email: info@partszf.com |
Phone: +86 158 2286 3467 |
Request a Quote →
