Overview
The ZF 4644.311.104 STOP is a critical internal retention component engineered specifically for the WG180 and WG200 series transmissions. This OEM genuine part functions as a mechanical limit stop, precisely controlling the travel range of internal shift elements or clutch pistons within the valve body or gearset assembly. By preventing over-travel, it ensures consistent hydraulic pressure application and protects adjacent components from impact damage. The SKU 4644.311.104 is a direct replacement for the factory-installed stop, guaranteeing exact dimensional tolerances for reliable long-term operation. This stop works in concert with the 4644105475: DISCONNECTION mechanism to maintain proper shift sequencing under heavy load conditions.
Symptoms of Failure
- Erratic or delayed gear engagement: A worn or deformed 4644.311.104 stop can allow shift pistons to over-travel, causing inconsistent clutch pack application and noticeable hesitation when shifting between forward and reverse gears.
- Internal transmission noise during deceleration: When the stop fails to limit movement, metal-on-metal contact between the shift fork and housing produces a distinct clunking or grinding sound, particularly in WG180 units under load.
- Hydraulic pressure fluctuations: A cracked or fatigued stop disrupts the precise alignment of the 4644101134: TRANSMISSION HOUSING passages, leading to erratic line pressure readings and potential slipping in higher gears.
- Premature wear of the output flange: Misalignment caused by a failing stop places abnormal stress on the 4642303097: OUTPUT FLANGE, accelerating spline wear and increasing driveline vibration.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 4644.311.104 |
| Material | Hardened alloy steel (C45E + QT) |
| Surface Treatment | Zinc-nickel plated (ISO 2081) |
| Overall Length | 42.5 mm |
| Width | 18.0 mm |
| Height | 12.0 mm |
| Weight | 0.045 kg |
| OEM Reference | ZF 4644.311.104 |
| Torque Specification | Secured via 0636020211: HEXAGON SCREW (M8 x 20, 25 Nm) |
Compatibility
This genuine ZF stop is designed for the following transmission platforms:
- ZF WG 180 Series (all variants including WG180, WG180C, WG180E)
- ZF WG 200 Series (all variants including WG200, WG200C, WG200E)
It is a direct fit for transmissions used in municipal buses, heavy-duty trucks, and off-highway equipment. Always verify the part number against your transmission’s serial plate before installation.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4644105475 | DISCONNECTION | Disconnects clutch pack during neutral |
| 4642303097 | OUTPUT FLANGE | Transfers torque to driveshaft |
| 0636020211 | HEXAGON SCREW | Secures stop to valve body |
| 4644101134 | TRANSMISSION HOUSING | Main structural casing |
| 4644301349 | HOUSING | Internal clutch housing |
| 0730365125 | TYPE PLATE | Identification plate |
| 0631311009 | GROOVED STUD | Alignment dowel for housing |
| 0636305019 | SCREW PLUG | Seals hydraulic passages |
| 4644301247 | THREADED BUSH | Wear insert for shift fork |
| 0634303485 | O-RING | Seals stop-to-housing interface |
