Overview
The ZF 0734.401.309 RECTANGULAR RING is a precision-engineered sealing component designed for the WG90, WG92, and WG98 series transmissions. This OEM genuine part sits at the critical interface between the TRANSMISSION HOUSING and the HOUSING II, forming a static seal that prevents fluid migration and maintains internal pressure integrity. Manufactured to ZF’s exacting tolerances, the 0734.401.309 rectangular ring ensures a leak-proof connection in high-vibration environments. Its rectangular cross-section provides superior compression resistance compared to standard O-rings, making it essential for long-term transmission reliability.
Symptoms of Failure
- External oil seepage at the housing joint: When the 0734.401.309 ring hardens or cracks, transmission fluid will visibly weep from the seam between the main housing and housing II, often leaving oily residue on the bell housing.
- Intermittent gear engagement hesitation: A degraded rectangular ring can cause internal pressure loss, leading to delayed clutch pack engagement and a “soft” shift feel during acceleration.
- Contaminated transmission fluid: A failed seal allows debris and moisture ingress through the housing interface, resulting in dark, gritty fluid and reduced lubrication efficiency.
- Audible hydraulic whine under load: Loss of seal integrity creates air entrainment in the oil circuit, producing a high-pitched whine that intensifies during torque converter lockup.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0734.401.309 |
| Cross-Section Shape | Rectangular (square-cut profile) |
| Material | Nitrile rubber (NBR) with high-temperature additive |
| Inside Diameter (approx.) | 180 mm |
| Cross-Section Width | 4.5 mm |
| Cross-Section Height | 3.2 mm |
| Weight | 28 grams |
| OEM Reference | ZF 0734.401.309 |
| Operating Temperature Range | -40°C to +120°C |
Compatibility
This rectangular ring is specifically engineered for ZF’s WG series powershift transmissions, including the WG90, WG92, WG94, and WG98 models. It is also compatible with the WG180 and WG200 variants where the same housing interface geometry is used. The 0734.401.309 ring directly replaces the original seal in the joint between the TRANSMISSION HOUSING and HOUSING II. For proper installation, ensure the mating surfaces are clean and free of old gasket material. Always pair this ring with a new CYLINDRICAL PIN to guarantee alignment, and verify the TYPE PLATE is correctly positioned before final assembly.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4660101017 | TRANSMISSION HOUSING | Main structural casing for gear train |
| 4660301054 | HOUSING II | Secondary housing cover for valve body |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for housing positioning |
| 0769123894 | TYPE PLATE | Identification tag for transmission model |
| 0750100022 | SCREW PLUG | Seals oil drain/fill ports |
| 4660221029 | SUCTION TUBE | Oil pickup from pan to pump |
| 0634100317 | O-RING | Static seal for suction tube connection |
| 0636103273 | CAP SCREW | Fastener for housing attachment |
| 0634306311 | O-RING | Seal for cap screw head |
| 4660321029 | FIXING PLATE | Retains oil filter assembly |
