Overview
The ZF 4143.020.079 2 HL 270 Hydrostatic Drive Assembly is a complete, factory-sealed unit engineered for the HL 100 and HL 270 series transmissions. This assembly integrates the hydraulic pump and motor into a single, pre-assembled module, converting engine power into infinitely variable hydraulic flow for precise vehicle speed and torque control. As the core of the hydrostatic circuit, it directly governs traction and maneuverability in heavy-duty industrial machinery. The SKU 4143.020.079 is a direct OEM replacement, ensuring exact fitment and eliminating the need for field assembly of individual components.
Symptoms of Failure
When the ZF 4143.020.079 hydrostatic drive begins to fail, operators will notice distinct performance degradation. Common failure symptoms include:
- Hydrostatic transmission slipping under load: The unit loses hydraulic pressure, causing the vehicle to creep or fail to maintain speed when climbing or pushing heavy loads.
- Excessive oil leaks from the drive housing: Worn seals or a cracked 4143101032: HOUSING can cause visible fluid loss around the assembly.
- Erratic or jerky forward/reverse engagement: Internal wear within the drive assembly leads to inconsistent hydraulic flow, resulting in harsh shifting or delayed response.
- Overheating of the transmission fluid: Internal bypassing or a blocked 4143301045: SCREEN SHEET causes excessive heat generation, often accompanied by a burnt oil smell.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4143.020.079 |
| Assembly Type | Complete Hydrostatic Drive Unit (2 HL 270) |
| Housing Material | High-Strength Aluminum Alloy (Die-Cast) |
| Dry Weight | Approx. 48 kg (106 lbs) |
| Overall Dimensions (L x W x H) | 420 mm x 320 mm x 280 mm |
| OEM Reference | ZF 2 HL 270 / HL 100 Series |
| Maximum Operating Pressure | 420 bar (6,090 psi) |
| Fluid Connection Type | SAE O-Ring Boss |
Compatibility
This complete hydrostatic drive assembly is specifically designed for ZF’s HL 100 and HL 270 series transmissions. It is a direct fit for models including the WG180, WG200, and WG210, where it serves as the primary hydraulic power source. The unit also integrates with the 4143301055: HOUSING and the 4143298040: CASE to form the complete transmission casing. For secure mounting, the 0631329135: SPRING PIN is used to align the drive assembly during installation. Always verify your transmission model and serial number before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101032 | HOUSING | Encloses the hydrostatic pump and motor assembly |
| 4143301055 | HOUSING | Rear section of the transmission case |
| 4143298040 | CASE | Main structural body of the transmission |
| 0631329135 | SPRING PIN | Alignment pin for drive assembly positioning |
| 0501214034 | SEALING CAP | Seals hydraulic ports during transport |
| 0636101024 | CAP SCREW | Secures housing sections together |
| 4475280099 | SCREW PLUG | Closes drain and test ports |
| 0634303266 | O-RING | Provides hydraulic seal between mating surfaces |
| 4143301045 | SCREEN SHEET | Filters debris from hydraulic fluid |
| 0636420051 | COUNTERSUNK SCREW | Low-profile fastener for internal components |
