Overview
The ZF 4644.123.001 CRAWLER for WG200 is a critical OEM genuine component designed to manage low-speed, high-torque output within the WG 200 series transmission. This part, identified by SKU 4644.123.001, functions as a dedicated reduction gear set that enables precise vehicle maneuvering at creep speeds, typically used in construction and agricultural machinery. It sits within the transmission’s auxiliary drive housing, engaging directly with the main shaft to provide controlled power delivery during heavy-load operations. When paired with the 4460165051: CONSOLE and the 4460368311: CONSOLE, this crawler assembly ensures seamless integration with the transmission’s hydraulic control system.
Symptoms of Failure
- Intermittent gear slipping during low-speed operation – A worn 4644.123.001 often causes the transmission to lose traction at crawl speeds, especially under load, leading to erratic movement and reduced operator control.
- Metallic grinding noise from the transmission housing – As the crawler gear teeth degrade, you may hear a distinct grinding or whining sound when engaging the creep mode, indicating internal wear or debris contamination.
- Hydraulic fluid leaks near the auxiliary drive – Damaged seals on the crawler assembly can allow transmission oil to escape, visible as drips or puddles around the WG200’s side cover, often accompanied by a burnt smell.
- Delayed engagement or failure to shift into crawl mode – A failing part may prevent the transmission from engaging the low-speed range, leaving the vehicle stuck in higher gears and unable to perform precision tasks.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4644.123.001 |
| OEM Reference | ZF 4644.123.001 |
| Material | Case-hardened alloy steel |
| Weight | 3.2 kg (7.05 lbs) |
| Dimensions (L x W x H) | 180 mm x 120 mm x 95 mm |
| Torque Capacity | Up to 450 Nm |
| Operating Temperature | -20°C to +120°C |
| Surface Treatment | Zinc-nickel plating |
Compatibility
This OEM genuine crawler is engineered specifically for the ZF WG 200 series transmissions, including the WG200, WG180, and WG150 variants. It is also compatible with select WG 211 models that share the same auxiliary drive architecture. For proper installation, ensure the 0636011429: HEXAGON SCREW and 0730100365: WASHER are replaced simultaneously to maintain correct clamping force and prevent vibration-induced loosening. The part is not backward-compatible with older WG 120 series units without a full adapter kit.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4460165051 | CONSOLE | Mounting bracket for hydraulic control valve |
| 4460368311 | CONSOLE | Secondary support for shift mechanism |
| 0636011429 | HEXAGON SCREW | Fastener for crawler assembly housing |
| 0730100365 | WASHER | Load-distributing spacer for bolt joints |
| 4644105418 | DISCONNECTION | Clutch disengagement actuator |
| 4644305041 | ADAPTER | Interface plate for auxiliary drive |
| 4460068159 | AXLE DRIVE | Output shaft power transfer unit |
| 4460168651 | INPUT FLANGE | Connection point for drive shaft |
| 4460368318 | FLANGE | Sealing cover for bearing housing |
| 4460368317 | DUST PROTECTION | Debris shield for input seal |
