Overview
The ZF 0899.312.909 CAP SCREW is a critical fastening component engineered specifically for the WG 200 series transmission assembly. This OEM genuine part secures the TRANSMISSION HOUSING and internal valve body assemblies, ensuring precise clamping force and vibration resistance under high-torque conditions. As a factory-spec fastener, the SKU 0899.312.909 maintains the structural integrity of the shift system and prevents fluid migration between sealed chambers. This cap screw is installed directly into threaded bores within the transmission case, where it anchors components like the DISCONNECTION mechanism and OUTPUT FLANGE assembly.
Symptoms of Failure
- Transmission fluid seepage around bolt heads: When the 0899.312.909 cap screw loses clamping tension, oil can bypass the sealing washer, leading to visible wet spots on the TRANSMISSION HOUSING exterior.
- Intermittent gear engagement hesitation: A loosened cap screw can cause micro-movement in the shift system, resulting in delayed or rough shifts during load changes.
- Unusual metallic rattling from the bell housing: If the fastener backs out partially, it may contact rotating components like the OUTPUT FLANGE, producing a distinct tapping noise at idle.
- Hydraulic pressure fluctuations: A compromised seal at the cap screw location disrupts oil flow to the HEXAGON SCREW ports, causing erratic clutch pack engagement.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 0899.312.909 |
| Thread Size | M10 x 1.5 (estimated) |
| Overall Length | 35 mm |
| Head Type | Hexagon socket cap |
| Material | Alloy steel, zinc-plated |
| Hardness Grade | 10.9 (estimated) |
| Weight | 0.045 kg |
| OEM Reference | ZF 0899.312.909 |
| Torque Specification | 45 Nm (factory spec) |
Compatibility
This cap screw is primarily designed for the ZF WG 200 series transmissions, including models WG200, WG210, and WG220. It also fits select WG180 variants produced after 2015, where the DISCONNECTION housing shares the same bolt pattern. The 0899.312.909 is not compatible with older Ecomat or Ecolife series without adapter kits. Always verify thread pitch against your transmission’s TYPE PLATE before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644105424 | DISCONNECTION | Isolates torque converter from driveline |
| 4644303538 | OUTPUT FLANGE | Transfers rotational force to driveshaft |
| 0636021036 | HEXAGON SCREW | Secures valve body to housing |
| 4644101224 | TRANSMISSION HOUSING | Main structural casing for gear sets |
| 4644301346 | TRANSMISSION HOUSING | Alternate housing variant for WG200 |
| 0730365067 | TYPE PLATE | Identification label with model specs |
| 4644106300 | SHIFT SYSTEM | Controls gear selection hydraulics |
| 4644306500 | COVER PLATE | Seals access port on housing |
| 4644159311 | SHIFT SYSTEM | Secondary shift actuator assembly |
| 4644306563 | VALVE BLOCK | Distributes hydraulic pressure |
