Overview
The ZF 4646.199.405 LOOSE PARTS set is a critical service kit designed specifically for the WG 251 series transmission. This genuine OEM assembly contains the essential loose components required to maintain the internal integrity of the gearbox, ensuring precise hydraulic pressure control and reliable torque transfer. The SKU 4646.199.405 is typically installed within the valve body or clutch pack region, acting as a seal and guide for moving pistons. When replacing this part, it is common to also inspect the TRANSMISSION HOUSING for cracks or wear, as the two components work in direct contact. Additionally, the HOUSING and COVER should be checked for alignment during reassembly, and all fasteners like the CAP SCREW must be torqued to specification.
Symptoms of Failure
When the 4646.199.405 LOOSE PARTS begin to degrade, operators will notice distinct operational issues. Delayed or harsh shifting is a primary indicator, as worn components fail to maintain proper clutch pack clearance. Internal oil leaks often develop around the piston seals, leading to low line pressure and erratic gear engagement. Another common symptom is transmission slippage under load, particularly in higher gears, which can be mistaken for torque converter failure. Finally, metallic debris in the oil pan may appear as the loose parts fracture, contaminating the entire hydraulic circuit.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 4646.199.405 |
| OEM Reference | ZF WG251 Series |
| Material | Hardened Steel / Sintered Metal |
| Weight | 0.85 kg (1.87 lbs) |
| Dimensions (L x W x H) | 120 mm x 80 mm x 25 mm |
| Finish | Zinc-Plated / Phosphate Coated |
| Bolt Torque | 25 Nm (18.4 ft-lbs) |
Compatibility
This genuine OEM part is engineered for the ZF WG 251 series, but its design principles allow it to be used in closely related models. The 4646.199.405 LOOSE PARTS set is compatible with the WG180, WG200, and WG250 transmissions that share the same valve body architecture. It also fits select WG210 and WG240 units where the piston bore dimensions match. Always verify the serial number on your transmission housing before installation. For complete assembly, consider pairing this kit with the COVER SHEET and SCREEN SHEET to ensure optimal filtration.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4646101143 | TRANSMISSION HOUSING | Main structural casing for gear assembly |
| 4646301202 | HOUSING | Secondary housing for valve body components |
| 4646301172 | COVER | Protective cover for internal mechanisms |
| 0636101051 | CAP SCREW | Fastener for securing housing sections |
| 4646201019 | COVER SHEET | Gasket or sealing sheet for oil passages |
| 4646301277 | SCREEN SHEET | Filter screen for hydraulic fluid |
| 0730365067 | TYPE PLATE | Identification plate for transmission model |
| 0631311009 | GROOVED STUD | Alignment stud for component positioning |
| 0636010216 | HEXAGON SCREW | M10 bolt for housing attachment |
| 0636010174 | HEXAGON SCREW | M8 bolt for cover fastening |
