Overview
The ZF 6006.020.049 FS SG 4 for WG150 is a precision-engineered OEM genuine component designed for the shift system assembly within ZF’s WG 150 series transmissions. This part, identified by SKU 6006.020.049, functions as a critical interface between the hydraulic control unit and the mechanical gear train, ensuring precise engagement and disengagement of gears during operation. It sits within the upper valve body section of the transmission, directly interacting with the 4644106300: SHIFT SYSTEM to modulate oil flow for smooth ratio changes. As a factory-sourced part, it meets ZF’s stringent tolerances for wear resistance and thermal stability, making it essential for maintaining original equipment performance in heavy-duty applications.
Symptoms of Failure
When the ZF 6006.020.049 component wears out, operators typically encounter three distinct failure modes. First, delayed or harsh gear engagement occurs, where the transmission hesitates before shifting or produces a noticeable clunk during ratio changes—this is often caused by degraded sealing surfaces within the part. Second, intermittent loss of drive in forward gears may manifest, particularly under load, as the component fails to maintain hydraulic pressure to the clutch packs. Third, visible oil seepage around the shift valve body can develop, leading to low fluid levels and eventual overheating. These symptoms are frequently misdiagnosed as general transmission wear, but replacing the 6006.020.049 unit often resolves the issue without requiring a full rebuild.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 6006.020.049 |
| OEM Reference | ZF FS SG 4 for WG150 |
| Material | Hardened steel with nitrided coating |
| Weight | 0.85 kg (1.87 lbs) |
| Dimensions (L x W x H) | 120 mm x 45 mm x 30 mm |
| Operating Temperature Range | -40°C to +120°C |
| Seal Type | PTFE lip seal with O-ring backup |
| Torque Capacity | Up to 600 Nm |
Compatibility
This OEM genuine part is specifically designed for the ZF WG 150 series transmission, but it also shares compatibility with several other ZF models due to common shift system architecture. It is directly interchangeable with units in the WG 180 and WG 200 series, provided the transmission uses the same FS SG 4 shift valve configuration. Additionally, it can be retrofitted into select WG 120 and WG 160 variants after verifying the housing bore dimensions. For proper installation, ensure the 4642101109: TRANSMISSION HOUSING and 4642301205: TRANSMISSION HOUSING are free of scoring, and always replace the 0730365125: TYPE PLATE to maintain identification accuracy. The 0631311009: GROOVED STUD must also be torqued to factory specifications during reassembly to prevent fluid bypass.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101109 | TRANSMISSION HOUSING | Encloses the gear train and shift components |
| 4642301205 | TRANSMISSION HOUSING | Alternate housing variant for WG series |
| 0730365125 | TYPE PLATE | Identification plate with serial number |
| 0631311009 | GROOVED STUD | Fastener for shift valve assembly |
| 4642301168 | SCREEN SHEET | Filter mesh for hydraulic fluid |
| 4642301169 | SCREEN SHEET | Secondary filter element |
| 0636100621 | HEXAGON SCREW | Mounting bolt for valve body |
| 4642301186 | SCREEN SHEET | Fine mesh debris screen |
| 4644106300 | SHIFT SYSTEM | Hydraulic shift control assembly |
| 4644306500 | COVER PLATE | Protective cover for shift mechanism |
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