ZF 4657.025.108 for WG190 | OEM Genuine Part

Overview

This OEM genuine ZF 4657.025.108 component is a critical internal actuator or shift element designed specifically for the WG 190 Series transmission. It functions as a hydraulic control piston or valve spool, managing oil flow to engage clutch packs and regulate gear shifts within the transmission housing. The SKU 4657.025.108 is engineered to exact ZF tolerances, ensuring precise modulation of line pressure during load changes. This part sits deep within the valve body assembly, directly interacting with the TRANSMISSION HOUSING and the HOUS.FRONT SECT to maintain proper hydraulic sealing.

Symptoms of Failure

• Erratic or delayed gear engagement: When the 4657.025.108 wears, internal leakage causes sluggish shifts, particularly when cold, as hydraulic pressure bleeds past worn sealing surfaces.
• Transmission slipping under load: A failing actuator cannot hold pressure, leading to clutch pack slippage during acceleration or hill climbs, often accompanied by a burning odor.
• Oil contamination from metallic debris: Abrasion of the part’s hardened surface sheds fine metal particles into the fluid, which can clog the SCREEN SHEET filters and damage downstream components.
• Intermittent neutral condition: Severe wear causes the transmission to drop into neutral unexpectedly, requiring immediate replacement to avoid catastrophic failure of the HOUSING REAR PART.

Technical Specifications

Compatibility

This genuine ZF 4657.025.108 is primarily designed for the WG 190 Series transmissions, including the WG190, WG190A, and WG190B variants. It is also compatible with the WG180 and WG200 series when used in conjunction with the correct HOUSING REAR SECTION. The part fits all ZF WG transmissions built after 2012 with a 6-bolt valve body pattern. Always verify the part number against your transmission’s serial plate before ordering.

Related Components

Frequently Asked Questions

Q: Can I replace the 4657.025.108 without removing the transmission from the vehicle?
A: Yes, in most WG190 installations, this part is accessible after dropping the transmission oil pan and removing the valve body cover. However, you must drain the fluid and replace the SCREEN SHEET filters simultaneously to prevent debris contamination.

Q: What torque specification should I use for the retaining bolts?
A: The two M6 cap screws securing this actuator require 12 Nm (9 ft-lbs) of torque. Do not overtighten, as this can distort the bore and cause binding. Always use new CAP SCREW fasteners for reassembly.

Q: How do I identify if my WG190 uses this specific part number?
A: Check the stamped code on the transmission data plate. If the serial number prefix is “WG190-46” or “WG190-47”, this 4657.025.108 actuator is the correct replacement. Units with earlier prefixes may require the HOUSING REAR SECTION adapter kit for proper fitment.