Overview
The ZF 4143.020.173 2 HL 270 Hydrostatic Drive Assembly is a complete, factory-sealed unit engineered for precise power delivery in heavy-duty industrial drivelines. This assembly integrates the pump and motor into a single, robust package, converting hydraulic pressure into smooth, variable-speed mechanical output. It sits at the core of the transmission system, directly managing torque flow to the final drive. The SKU 4143.020.173 is a direct replacement for worn or failed assemblies, ensuring your ZF HL 100 or HL 270 series transmission returns to peak operational efficiency. When rebuilding this section, technicians often pair it with a new 4143101043: HOUSING and the 4143301055: HOUSING to guarantee a sealed, leak-free interface.
Symptoms of Failure
Recognizing early warning signs of a failing hydrostatic drive assembly can prevent catastrophic system damage. Watch for these specific failure symptoms:
- Erratic machine creep or “shuddering” under load: If the drive assembly cannot maintain consistent hydraulic pressure, the vehicle will lurch or vibrate during operation, especially when starting from a stop.
- Chronic oil leaks around the pump-to-motor junction: Worn seals or a cracked 4143298040: CASE will allow hydraulic fluid to escape, leading to low oil levels and eventual pump cavitation.
- Complete loss of forward or reverse drive: Internal piston wear or a broken swashplate can cause a total loss of hydraulic flow, leaving the machine immobile despite the engine running.
- Excessive noise (whining or grinding) from the transmission housing: Metal debris from a failing bearing or gear set inside the assembly will produce a distinct, high-pitched whine that worsens with speed.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number / SKU | 4143.020.173 |
| Assembly Type | 2 HL 270 Hydrostatic Drive (Complete Unit) |
| OEM Reference | ZF 2 HL 270 |
| Housing Material | High-strength cast iron (GGG-40) |
| Dry Weight (approx.) | 42.5 kg (93.7 lbs) |
| Overall Length | 385 mm |
| Mounting Bolt Pattern | 4-bolt SAE A (standard) |
| Max Operating Pressure | 420 bar (6,090 psi) |
Compatibility
This hydrostatic drive assembly is specifically engineered for the ZF HL 100 and HL 270 series transmissions. It is a direct fit for models including the WG180, WG200, and WG210, which share the same hydraulic architecture. The unit also integrates with the 2 HL 270 variant found in many mid-size wheel loaders and telehandlers. Always verify the mounting flange and spline count match your existing 0631329135: SPRING PIN alignment before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101043 | HOUSING | Encloses the drive assembly, providing structural support and fluid channels. |
| 4143301055 | HOUSING | Secondary housing for the motor section, ensures proper bearing alignment. |
| 4143298040 | CASE | Outer casing that protects internal gears and retains lubricant. |
| 0631329135 | SPRING PIN | Secures linkage components; prevents rotational movement of shafts. |
| 0501214034 | SEALING CAP | Seals hydraulic ports to prevent contamination during assembly. |
| 0636101024 | CAP SCREW | High-tensile fastener for mounting the drive unit to the transmission. |
| 4475280099 | SCREW PLUG | Seals oil galleries and test ports in the housing. |
| 0634303266 | O-RING | Provides a static seal between housing halves to prevent fluid leaks. |
| 4143301045 | SCREEN SHEET | Filters debris from hydraulic fluid before it enters the pump. |
| 0636420051 | COUNTERSUNK SCREW | Flush-mount fastener for securing the screen sheet inside the housing. |
