ZF 0634.313.867 O-RING for WG250/WG258/WG308 | OEM Genuine Part

Overview

The ZF 0634.313.867 O-RING is a precision-engineered sealing component designed for use in the hydraulic control circuits of heavy-duty ZF WG-series powershift transmissions. This OEM genuine part, identified by SKU 0634.313.867, sits between the transmission housing and the valve body or cover plate assembly, where it prevents pressurized oil from bypassing critical lubrication and clutch actuation passages. By maintaining a positive seal under high thermal and pressure cycles, this O-ring ensures consistent hydraulic pressure delivery to the clutch packs and planetary gear sets. When installed alongside the 4646101028: TRANSMISSION HOUSING and the 4646301095: HOUSING, it completes the primary sealing boundary for the main gear train.

Symptoms of Failure

• External oil seepage at the housing-to-cover interface: A worn or hardened 0634.313.867 O-ring allows transmission fluid to weep past the mating surface, leaving visible drips or a wet film on the bell housing.
• Erratic clutch engagement or gear slipping: When the seal fails internally, hydraulic pressure bleeds off, causing delayed shifts or momentary loss of torque during power-on upshifts.
• Low transmission fluid level without visible external leaks: Internal cross-leakage through a degraded O-ring can redirect oil into the sump or cooler circuit, leading to a false low-level reading on the dipstick.
• Increased operating temperature: A compromised seal forces the hydraulic pump to work harder to maintain pressure, generating excess heat that can accelerate wear on adjacent components like the 4646301087: COVER.

Technical Specifications

Compatibility

This O-ring is a direct-fit sealing element for ZF WG-series powershift transmissions, specifically engineered for models that share a common hydraulic manifold architecture. Verified compatible series include the WG 250, WG 251, WG 258, WG 260, WG 261, WG 308, WG 310, and WG 311. It is also commonly used in the WG180 and WG200 variants where the valve body is secured by a 0636015304: HEXAGON SCREW. Always confirm the O-ring groove diameter in your specific housing before installation.

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