Overview
The ZF 0730.007.791 RING is a precision-engineered sealing component designed for the clutch and planetary gear assemblies within the WG200, WG201, and WG250 series transmissions. This OEM genuine part functions as a critical static and dynamic seal, preventing pressurized hydraulic fluid from bypassing piston chambers and ensuring proper clutch pack engagement. The SKU 0730.007.791 is installed directly onto the transmission housing bore, where it interfaces with rotating shafts to maintain system pressure. When paired with a robust TRANSMISSION HOUSING, this ring guarantees the integrity of the hydraulic circuit, which is essential for smooth gear shifts and torque converter lock-up.
Symptoms of Failure
- Delayed or harsh gear engagement: A worn 0730.007.791 ring allows internal pressure loss, causing the transmission to hesitate before engaging drive or reverse, particularly in WG200 series units.
- Hydraulic fluid seepage near the bell housing: When the ring degrades, ATF can escape past the seal, leaving visible drips on the transmission exterior and a burnt fluid smell during operation.
- Intermittent slipping under load: As the ring loses its sealing ability, the clutch packs fail to hold torque, resulting in RPM flare-ups during acceleration in WG250 models.
- Erratic shift timing: Pressure fluctuations caused by a failing ring confuse the valve body, leading to early or late shifts that feel unpredictable.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 0730.007.791 |
| Material | Nitrile rubber (NBR) with steel reinforcement |
| Inner Diameter | ~85 mm (estimated) |
| Outer Diameter | ~98 mm (estimated) |
| Thickness | ~4.5 mm (estimated) |
| Weight | ~0.03 kg |
| OEM Reference | ZF 0730.007.791 |
| Operating Temperature Range | -40°C to +150°C |
Compatibility
This genuine ZF ring is engineered for the following transmission models: WG180, WG200, WG201, WG250, and select WG310 variants that share the same clutch housing architecture. It is a direct replacement for the original seal in the piston retainer assembly. For a complete rebuild, always inspect the TRANSMISSION HOUSING for scoring or wear, and verify the TYPE PLATE to confirm the exact transmission series. The ring is secured in place using a GROOVED STUD that prevents rotation during operation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101175 | TRANSMISSION HOUSING | Encloses the gear train and supports the ring seal bore |
| 4644301221 | TRANSMISSION HOUSING | Alternate housing variant for WG200 series |
| 0730365067 | TYPE PLATE | Identification plate for transmission model verification |
| 0631311009 | GROOVED STUD | Retains the ring in its groove during assembly |
| 4644303060 | COVER PLATE | Seals the clutch piston access port |
| 4644303061 | COVER PLATE | Alternate cover plate for different housing castings |
| 0634306525 | O-RING | Secondary seal for the cover plate interface |
| 0636305026 | SCREW PLUG | Seals the pressure test port on the housing |
| 0501316470 | BREATHER | Vents internal pressure to prevent seal blowout |
| 4644301279 | SCREEN SHEET | Filters debris from the hydraulic circuit |
