Overview
The ZF 4143.020.262 2 HL 290 Hydrostatic Drive Assembly is a complete, factory-matched unit designed for precise power transfer in heavy-duty mobile machinery. This assembly integrates the pump and motor into a single sealed package, converting hydraulic flow into controlled mechanical rotation for vehicle propulsion or implement drive. As a core component of the HL 100 and HL 270 series, the SKU 4143.020.262 replaces the original 2 HL 290 unit, ensuring direct bolt-on fitment. It works in concert with the 4143101046 HOUSING and the 4143301055 HOUSING to contain high-pressure oil and maintain internal alignment. The assembly also relies on the 4143298040 CASE for structural rigidity and the 0631329135 SPRING PIN for precise dowel alignment during installation.
Symptoms of Failure
- Hydrostatic drive slipping under load: When the 2 HL 290 assembly wears internally, the unit fails to maintain pressure, causing the machine to lose traction or speed during heavy operation.
- External oil leaks at housing joints: Deteriorated seals or cracked castings around the 4143101046 HOUSING or 4143301055 HOUSING result in visible hydraulic fluid drips, often accompanied by a burnt smell.
- Excessive noise or whining during operation: Worn bearings or cavitation within the drive assembly produce a high-pitched whine, indicating imminent failure of the rotating group.
- Erratic or jerky movement: Internal contamination or scoring in the cylinder block causes uneven power delivery, making smooth acceleration impossible.
Technical Specifications
| Parameter | Specification |
|---|---|
| Product Type | Complete Hydrostatic Drive Assembly |
| OEM Reference | ZF 2 HL 290 |
| Overall Length | 420 mm (approx.) |
| Overall Width | 280 mm (approx.) |
| Dry Weight | 38 kg (84 lbs) |
| Housing Material | High-strength cast iron |
| Maximum Operating Pressure | 420 bar (6,100 psi) |
| Displacement | 90 cc/rev (pump side) |
| Mounting Pattern | SAE A 2-bolt |
Compatibility
This ZF 4143.020.262 assembly is engineered for the HL 100 and HL 270 series of hydrostatic transmissions. It directly replaces units in ZF WG180, WG200, and WG250 driveline configurations where a 2 HL 290 pump-motor package is specified. It also fits select models in the ZF 4WG-200 and 4WG-310 series that utilize the HL 290 architecture. Always verify the original part number and housing casting codes before ordering.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4143101046 | HOUSING | Encloses the pump rotating group |
| 4143301055 | HOUSING | Encloses the motor rotating group |
| 4143298040 | CASE | Main structural body of the drive |
| 0631329135 | SPRING PIN | Aligns housing halves during assembly |
| 0501214034 | SEALING CAP | Seals unused port openings |
| 0636101024 | CAP SCREW | Secures housing to case |
| 4475280099 | SCREW PLUG | Closes drain and test ports |
| 0634303266 | O-RING | Seals housing interfaces |
| 0501200072 | VENT VALVE | Relieves internal case pressure |
| 0501217673 | LUBRICATING NIPPLE | Grease fitting for shaft bearing |
