Overview
The ZF 4143.020.051 2 HL 290 Hydrostatic Drive Assembly is a complete, high-pressure hydraulic unit engineered for precise speed and torque control in heavy-duty ZF transmissions. This assembly integrates the pump and motor into a single, sealed package, converting engine power into smooth, variable hydraulic flow for steering and propulsion systems. As a direct replacement for the HL 100 and HL 270 series, the SKU 4143.020.051 ensures your equipment maintains its original ZF performance specifications. This unit is commonly paired with the 4143101031: HOUSING and the 4143301055: HOUSING to form the complete hydraulic circuit within the transmission casing.
Symptoms of Failure
When the ZF 4143.020.051 hydrostatic drive begins to fail, operators typically notice these specific issues:
- Erratic machine creep or sudden loss of drive: The unit may fail to maintain consistent pressure, causing the vehicle to drift unexpectedly or lose all forward/reverse motion under load.
- Excessive hydraulic oil foaming or overheating: Internal wear in the drive assembly creates cavitation, leading to aerated oil and localized hot spots that degrade system seals.
- Whining or grinding noise during operation: Worn pistons or a damaged swashplate produce a high-pitched whine or metallic grinding sound, especially during directional shifts.
- External oil seepage from the drive housing: Cracks or seal failures in the assembly allow pressurized oil to leak past the 0631329135: SPRING PIN and adjacent gasket surfaces.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 4143.020.051 |
| Assembly Type | 2 HL 290 Hydrostatic Drive (Complete Unit) |
| Displacement | 290 cc/rev (estimated) |
| Maximum Operating Pressure | 420 bar (6,090 psi) |
| Housing Material | High-strength cast iron |
| Dry Weight | Approx. 85 kg (187 lbs) |
| OEM Reference | ZF 4143.020.051 |
| Mounting Flange | SAE B 2-bolt (estimated) |
Compatibility
This hydrostatic drive assembly is designed for use in ZF WG and ERG series transmissions that require a 290 cc hydraulic unit. It is a direct fit for the ZF WG180, WG200, and WG210 models, as well as the ERG 100 and ERG 200 series. The assembly also integrates with the 4143298040: CASE to ensure proper alignment of the internal rotating group. Always verify your transmission model and serial number before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101031 | HOUSING | Encloses the drive assembly and supports internal bearings |
| 4143301055 | HOUSING | Secondary housing for valve block and porting |
| 4143298040 | CASE | Main transmission case that houses the hydrostatic unit |
| 0631329135 | SPRING PIN | Secures linkage and control components |
| 0636101024 | CAP SCREW | Fastens housing sections together |
| 4475280099 | SCREW PLUG | Seals hydraulic ports and test points |
| 0634303266 | O-RING | Provides static seal between mating surfaces |
| 4143301045 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 0636420051 | COUNTERSUNK SCREW | Low-profile fastener for valve plate |
| 0501200072 | VENT VALVE | Relieves case pressure and prevents contamination |
