Overview
The ZF 4143.020.138 2 HL 290 Hydrostatic Drive Assembly is a complete, factory-matched unit designed for the demanding power-split drivelines found in ZF HL 100 and HL 270 series transmissions. This assembly integrates the hydrostatic motor and pump into a single, sealed module, providing infinitely variable speed control and precise torque management for heavy-duty mobile machinery. The SKU 4143.020.138 is the direct OEM replacement for the original 2 HL 290 configuration, ensuring exact fitment and hydraulic performance. Within the transmission architecture, this drive assembly sits between the main gearbox housing and the final drive, converting hydraulic pressure into mechanical rotation. For proper sealing and structural integrity, this unit mounts directly against the 4143101046: HOUSING and the 4143301055: HOUSING, which form the outer casing of the assembly.
Symptoms of Failure
- Hydrostatic drive slipping under load: When the 2 HL 290 unit wears, you will notice a loss of traction or speed during heavy pushing or grading operations, often accompanied by erratic wheel speeds.
- External oil leaks from the drive housing: Worn seals or a cracked 4143298040: CASE will cause visible hydraulic fluid seepage around the drive assembly, particularly near the input shaft and mounting flanges.
- Excessive noise or whining during operation: Internal bearing or piston wear produces a high-pitched whine or grinding sound that increases with engine RPM, indicating imminent hydrostatic failure.
- Erratic or jerky vehicle movement: A failing hydrostatic drive assembly will cause sudden lurching or hesitation when engaging forward or reverse, due to pressure loss in the closed-loop circuit.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4143.020.138 |
| Assembly Type | 2 HL 290 Hydrostatic Drive (Complete Unit) |
| OEM Reference | ZF 2 HL 290 |
| Housing Material | High-strength cast iron (GGG-40) |
| Dry Weight | Approx. 48 kg (106 lbs) |
| Overall Length | 410 mm |
| Mounting Bolt Pattern | 6x M16 on 180 mm PCD |
| Sealing System | Integrated O-rings and shaft seals |
| Related Sealing Part | 0634303266: O-RING |
| Fastener Kit Reference | 0636101024: CAP SCREW |
Compatibility
This hydrostatic drive assembly is engineered for ZF transmissions in the HL 100 and HL 270 series families. It is a direct fit for the following ZF models: WG180, WG200, WG210, and WG250. Additionally, it is commonly used in HL 270 and HL 290 final drive configurations. The unit is also compatible with earlier 4WG-180 and 4WG-200 power-shift transmissions that utilize a separate hydrostatic pump module. Always verify the mounting interface and spline count against your existing assembly before installation. The unit is secured using a 0631329135: SPRING PIN for alignment, and the hydraulic circuit is sealed with a 0501214034: SEALING CAP and a 4475280099: SCREW PLUG.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101046 | HOUSING | Outer casing for the hydrostatic drive assembly |
| 4143301055 | HOUSING | Secondary housing for bearing support |
| 4143298040 | CASE | Structural case enclosing the gear train |
| 0631329135 | SPRING PIN | Alignment pin for housing assembly |
| 0501214034 | SEALING CAP | Protects hydraulic ports during transport |
| 0636101024 | CAP SCREW | Fastener for mounting the drive unit |
| 4475280099 | SCREW PLUG | Seals oil passages in the housing |
| 0634303266 | O-RING | Hydraulic seal between mating surfaces |
| 0501200072 | VENT VALVE | Relieves internal pressure in the housing |
| 0501217673 | LUBRICATING NIPPLE | Grease fitting for bearing maintenance |
