Overview
The ZF 4644.159.344 SHIFT SYSTEM is a precision-engineered OEM genuine component designed exclusively for the WG150 series transmission. This critical assembly governs the hydraulic selection of forward, neutral, and reverse gears by directing oil flow through the valve body. Positioned within the main control unit of the transmission, the shift system ensures smooth engagement and disengagement of clutch packs under varying load conditions. The SKU 4644.159.344 is manufactured to ZF’s original tolerances, guaranteeing direct interchangeability without modification. When paired with a robust TRANSMISSION HOUSING (4642101109) or the alternative TRANSMISSION HOUSING (4642301205), this shift system delivers reliable performance in heavy-duty industrial applications.
Symptoms of Failure
- Delayed or harsh gear engagement: Worn spools or seals within the shift system cause hesitation when shifting from neutral to drive or reverse, often accompanied by a jarring clunk.
- Intermittent gear slipping under load: As internal components degrade, the system fails to maintain proper hydraulic pressure, leading to momentary loss of power transfer during acceleration.
- Oil leaks around the shift valve body: Cracks or fatigued O-rings in the 4644.159.344 assembly allow transmission fluid to seep externally, leaving visible drips beneath the vehicle.
- Erratic shift patterns or stuck in gear: A failing shift system may cause the transmission to remain locked in one gear or skip gears unexpectedly, compromising drivability.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number (SKU) | 4644.159.344 |
| OEM Reference | ZF 4644.159.344 |
| Material | High-strength aluminum alloy with hardened steel spools |
| Weight | 1.8 kg (4.0 lbs) |
| Dimensions (L x W x H) | 210 mm x 120 mm x 85 mm |
| Operating Pressure Range | 10–18 bar |
| Seal Type | Nitrile rubber O-rings (included) |
| Compatible Housing | 4642101109 / 4642301205 |
Compatibility
This shift system is engineered for the ZF WG150 series transmission. It is also mechanically compatible with the WG180 and WG200 series when used with the correct housing adapter. The 4644.159.344 unit directly replaces earlier revision shift systems in WG150 applications. For proper identification, always verify the TYPE PLATE (0730365125) on your transmission to confirm model and serial number. Additionally, ensure the GROOVED STUD (0631311009) is torqued to specification during installation to prevent misalignment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4642101109 | TRANSMISSION HOUSING | Encloses and supports the shift system and gear train |
| 4642301205 | TRANSMISSION HOUSING | Alternate housing variant for WG150 series |
| 0730365125 | TYPE PLATE | Identification plate with transmission model and specs |
| 0631311009 | GROOVED STUD | Secures shift system to housing with precise alignment |
| 4642301168 | SCREEN SHEET | Filters debris from hydraulic fluid entering shift system |
| 4642301169 | SCREEN SHEET | Fine-mesh filter for secondary hydraulic circuits |
| 0636100621 | HEXAGON SCREW | Fastener for mounting shift valve body to housing |
| 4642301186 | SCREEN SHEET | High-flow filter for heavy-duty applications |
| 4644106324 | SHIFT SYSTEM | Alternate shift system variant for WG200 series |
| 4644306598 | PLATE | Cover plate protecting shift system internals |
ZF 4644.159.344 SHIFT SYSTEM – Shift System RFQ Support
ZF 4644.159.344 SHIFT SYSTEM can be reviewed as a shift-system sourcing item for WG, BP, HL, or ERGOPOWER-related service work when the application evidence is available.
Part-Number Summary
Use ZF number 4644.159.344 when sending your RFQ. PartsZF can review dotted, spaced, and compact number formats against the available product and documentation records.
Application Context
- Illustration section: SHIFT SYSTEM
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 | 4644.159.344 |
|---|---|
| Normalized SKU | 4644159344 |
| Part name | SHIFT SYSTEM |
| Product category | shift system |
| 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.
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- ZF 4644.159.303 SHIFT SYSTEM
