ZF 8605.955.103 RADIAL PISTON PUMP for WG200 | OEM Genuine Part

Overview

The ZF 8605.955.103 Radial Piston Pump is a critical hydraulic component engineered specifically for the WG 200 series powershift transmission. This OEM genuine part serves as the primary hydraulic power source, converting mechanical energy from the transmission’s input shaft into high-pressure fluid flow. Positioned within the transmission’s pump drive assembly, the SKU 8605.955.103 supplies pressurized oil to actuate clutch packs, modulate shift pressures, and lubricate internal gears. Without this pump, the transmission cannot generate the hydraulic force required for smooth gear engagement or torque converter operation. As a direct replacement for the original factory unit, this radial piston pump ensures precise flow rates and pressure stability, maintaining the WG200’s renowned durability in heavy-duty off-highway applications.

Symptoms of Failure

• Intermittent gear slipping under load: When the 8605.955.103 pump loses internal sealing, hydraulic pressure drops, causing clutch packs to slip during acceleration or uphill operation.
• Visible oil leaks near the pump mounting flange: Worn piston rings or a cracked housing allow transmission fluid to escape, often pooling beneath the bell housing area.
• Delayed or harsh shifting: Reduced flow from a failing radial piston pump results in sluggish clutch fill times, producing jarring engagement between forward and reverse gears.
• Elevated operating temperatures: A pump operating at reduced efficiency forces the transmission to work harder, generating excess heat that can degrade fluid and damage seals.

Technical Specifications

Compatibility

This radial piston pump is designed primarily for the ZF WG 200 series transmission, including models WG200, WG201, and WG210. It also fits select WG180 variants that share the same pump drive geometry. The 8605.955.103 is not compatible with older WG120 or WG150 series units without adapter modifications. For proper installation, verify that your transmission’s pump cavity matches the flange pattern of this OEM unit. When replacing this pump, always inspect the 4644105414 DISCONNECTION coupling for wear, as a damaged drive tang can cause premature pump failure. Additionally, check the 4644303409 OUTPUT FLANGE for runout, and torque all 0636021083 HEXAGON SCREW fasteners to factory specifications. The pump mounts directly to the 4644101231 TRANSMISSION HOUSING, so ensure the mating surface is clean and free of debris.

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