ZF 4646.137.012 EMERGENCY STEERING PUMP for WG250 | OEM Genuine Part

Overview

The ZF 4646.137.012 EMERGENCY STEERING PUMP is a critical hydraulic component engineered specifically for the WG 250 Series transmission. This OEM genuine part provides an auxiliary steering function, ensuring that the vehicle retains directional control if the primary steering system loses pressure. Mounted directly to the transmission housing, the pump draws hydraulic fluid from the main circuit to maintain steering capability during engine stall or pump failure. The SKU 4646.137.012 is precision-machined to ZF’s exacting tolerances, guaranteeing seamless integration with the TRANSMISSION HOUSING and the HOUSING assembly.

Symptoms of Failure

• Steering wheel becomes stiff or unresponsive during low-engine RPM: A worn emergency steering pump fails to generate sufficient hydraulic pressure, causing the steering to feel heavy or lock up, especially in tight maneuvers.
• Audible whining or grinding noise from the transmission area: Internal bearing wear or cavitation within the pump produces a high-pitched whine, indicating imminent failure of the 4646.137.012 unit.
• Hydraulic fluid leaks near the pump mounting flange: Deteriorated seals or a cracked pump body allow ATF to escape, leaving puddles under the vehicle and reducing system pressure.
• Intermittent loss of steering assist under load: When the pump cannot maintain flow, the steering may suddenly become heavy during turns, a clear sign the emergency pump needs replacement.

Technical Specifications

Compatibility

This emergency steering pump is primarily designed for the ZF WG 250 Series transmission. Based on its hydraulic architecture and mounting interface, the 4646.137.012 is also compatible with the following ZF models: WG 180, WG 200, and WG 240. It integrates directly with the COVER and the CONNECTING PART to form a sealed hydraulic circuit. Always verify your transmission serial number before ordering.

Related Components