ZF 4143.070.058 2 HL 70 Hydrostatic Drive Assembly | Complete Unit

Overview

The ZF 4143.070.058 2 HL 70 Hydrostatic Drive Assembly is a complete, pre-assembled unit engineered for the HL 100 and HL 270 series transmissions. This assembly functions as the primary hydraulic power transfer module, converting engine torque into variable-speed hydrostatic drive for heavy-duty mobile equipment. The SKU 4143.070.058 integrates the pump and motor housing into a single sealed unit, ensuring precise oil flow control and high-pressure operation. When replacing this assembly, it is critical to inspect the adjacent 4143101017: HOUSING and the 4143301039: HOUSING for wear, as these components form the structural backbone of the transmission case.

Symptoms of Failure

• Hydrostatic drive slipping under load: If the 2 HL 70 assembly loses internal seal integrity, you will notice a gradual loss of power transfer when the machine is under heavy load, often accompanied by a whining noise from the pump section.
• External oil leaks at the housing interface: Worn O-rings or a cracked housing can cause hydraulic fluid to weep from the joint between the drive assembly and the main case. This is a common failure point that requires immediate replacement of the 0501318136: GASKET and the 0636101084: CAP SCREW set.
• Erratic speed control or jerky operation: Internal contamination or scoring of the valve plate within the 4143.070.058 unit can cause the machine to surge or hesitate during acceleration, indicating the need for a complete unit replacement.
• Overheating of the transmission fluid: A failing hydrostatic drive assembly can generate excessive heat due to internal bypassing, leading to degraded oil viscosity and potential thermal damage to surrounding seals.

Technical Specifications

Compatibility

This hydrostatic drive assembly is designed for ZF transmissions in the HL 100 and HL 270 series. It is a direct fit for models including the WG180, WG200, and WG210 series, where the 2 HL 70 unit is used as the primary drive module. It also retrofits into earlier WG150 and WG170 transmissions that have been upgraded to the HL series housing configuration. Always verify the mounting flange pattern and spline count against your existing unit before installation. For proper sealing, use the 0750108044: PLUG and 0636302014: SCREW PLUG to close any unused ports during installation.

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