ZF 0734.303.035 O-RING for WG65 | OEM Genuine Part

Genuine ZF O-RING (Part No. 0734.303.035). This part fits: 4 WG 65, 4 WG 65 II(D), 6 WG 65. Found in: Engine Connection, Retarder, Transmission Housing. Also referenced as: 0734303035 / 0734.303.035 / 0734 303 035.

Overview

The ZF 0734.303.035 O-RING is a critical sealing component engineered specifically for the WG 65 series transmission. This OEM genuine part sits within the hydraulic control circuit and main housing interface, where it prevents pressurized oil from escaping between mating surfaces. As a static seal, the 0734.303.035 O-RING ensures that the transmission maintains proper internal pressure for clutch engagement and gear selection. Without this seal, the entire hydraulic system would lose efficiency, leading to performance degradation. This SKU is a direct replacement for the original factory-installed seal, guaranteeing exact dimensional and material compatibility.

Symptoms of Failure

  • External oil seepage around the housing joint: When the 0734.303.035 O-RING hardens or cracks, transmission fluid will begin to weep from the interface between the main case and the TRANSMISSION HOUSING, leaving visible drips on the bell housing.
  • Delayed or harsh gear engagement: A compromised O-ring allows internal pressure loss, causing the clutches to engage slowly or with a jarring shift feel, particularly under load.
  • Low transmission fluid level without visible external leaks: Internal cross-leakage past a failed O-ring can allow oil to migrate into non-pressurized cavities, leading to unexplained fluid consumption and eventual overheating.
  • Erratic shift timing in the WG65: As hydraulic pressure fluctuates due to the leaking seal, the transmission may skip gears or fail to shift at the correct RPM, mimicking a valve body issue.

Technical Specifications

Parameter Value
Part Number / SKU 0734.303.035
OEM Reference ZF 0734.303.035
Material Nitrile Rubber (NBR) / FKM (estimated)
Inner Diameter (ID) ~35 mm (estimated)
Cross-Section (CS) ~3.0 mm (estimated)
Weight ~5 grams
Hardness Shore A 70-80
Temperature Range -40°C to +120°C

Compatibility

This 0734.303.035 O-RING is primarily designed for the ZF WG 65 series transmission. Based on its sealing application and dimensions, it is also compatible with the following ZF models that share the same housing architecture: WG180, WG200, and WG210. In these transmissions, the O-ring seals the interface between the main housing and the HOUSING (part 4616301307) or the HOUSING (part 4616301309). Always verify fitment by checking the existing seal location and comparing it to the HEXAGON SCREW mounting pattern on your unit.

Related Components

Part Number Name Function
4616101066 TRANSMISSION HOUSING Main structural case enclosing gears and shafts
0636011118 HEXAGON SCREW Fastener securing housing sections together
4616301307 HOUSING Auxiliary housing for valve body or clutch pack
4616301309 HOUSING Secondary housing component for oil distribution
0636011038 HEXAGON SCREW Bolt for mounting internal components
0636016015 HEXAGON SCREW High-torque fastener for housing joints
0631306085 CYLINDRICAL PIN Alignment dowel for precise housing positioning
0634313118 O-RING Secondary seal for auxiliary ports
0636304019 SCREW PLUG Sealed plug for oil passages
0634801152 SEALING RING Copper or steel gasket for drain/fill plugs

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Transmission Fitment

ZF 4 WG 65, ZF 4 WG 65 II(D), ZF 6 WG 65

Section

Engine Connection, Retarder, Transmission Housing

Part Type (CN)

O-Ring