Overview
The ZF 4644.108.200 COUNTERSHAFT is a critical internal component designed for the WG 201 series of heavy-duty transmissions. This OEM genuine part serves as the primary torque-transfer shaft, synchronizing gear rotation within the transmission housing to ensure smooth power delivery from the engine to the driveline. Positioned parallel to the main shaft, the countershaft engages with multiple gear sets to provide the necessary gear ratios for commercial vehicles and industrial machinery. The SKU 4644.108.200 is precision-machined to ZF’s exacting tolerances, making it an essential replacement for maintaining transmission integrity and operational efficiency.
Symptoms of Failure
When the ZF 4644.108.200 countershaft begins to wear, operators may notice several distinct failure indicators. Gear grinding or hard shifting often occurs as the countershaft’s bearing surfaces degrade, causing misalignment between gear teeth. Unusual whining or rumbling noises from the transmission, particularly under load, signal bearing fatigue or shaft scoring. Intermittent power loss or gear slipping can result from worn splines that fail to maintain positive engagement with mating gears. Additionally, metal particles in the transmission fluid are a clear sign of countershaft material fatigue, requiring immediate inspection to prevent catastrophic failure.
Technical Specifications
| Part Number | 4644.108.200 |
| OEM Reference | ZF WG 201 Series |
| Material | Case-hardened alloy steel (20MnCr5 equivalent) |
| Overall Length | 485 mm |
| Diameter | 55 mm (bearing journal) |
| Weight | 8.7 kg |
| Surface Treatment | Nitrided for wear resistance |
| Spline Count | 24 involute splines |
Compatibility
This countershaft is engineered for the ZF WG 201 transmission family, which includes the WG180, WG200, and WG210 variants. It is directly compatible with all WG 201 series models used in municipal trucks, refuse vehicles, and construction equipment. The part also fits select WG 200 series units where the countershaft geometry matches the 4644.108.200 specification. For proper installation, this shaft must be paired with a matching TRANSMISSION HOUSING (4644101203) or the TRANSMISSION HOUSING (4644301382) to ensure correct alignment. Secure the assembly using a SCREW PLUG (0636302005) and a THREADED BUSH (4644301189) for oil retention and structural integrity.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644101203 | TRANSMISSION HOUSING | Encloses and supports the countershaft assembly |
| 4644301382 | TRANSMISSION HOUSING | Alternate housing variant for WG201 models |
| 4644301189 | THREADED BUSH | Provides threaded mounting point for housing bolts |
| 0636302005 | SCREW PLUG | Seals oil passages in the housing |
| 0634306198 | O-RING | Prevents fluid leaks at shaft interfaces |
| 0634801098 | SEALING RING | Ensures oil-tight seal on bearing journals |
| 0730365067 | TYPE PLATE | Identifies transmission model and serial number |
| 0631311009 | GROOVED STUD | Secures housing components with anti-rotation feature |
| 4644301161 | COVER PLATE | Protects countershaft access opening |
| 0636100621 | HEXAGON SCREW | Fastens cover plate and housing sections |
