Overview
The ZF 4644.036.040 6 WG 201 Powershift Transmission Assembly is a complete, factory-sealed unit designed for heavy-duty off-highway machinery. This assembly serves as the primary power transfer module, integrating the torque converter, planetary gear sets, and hydraulic control system into a single, ready-to-install package. As a core component of the WG 201 series, it manages torque multiplication and gear ratio selection under high-stress conditions. The SKU 4644.036.040 identifies this specific variant, which includes updated clutch packs and hardened output shafts for extended service life in loader and dozer applications.
Symptoms of Failure
When the ZF 4644.036.040 assembly begins to degrade, operators will notice distinct performance issues. Common failure indicators include:
- Delayed engagement or gear slippage – A worn clutch pack or degraded sealing rings cause the transmission to hesitate before moving or to lose power under load, especially in forward gears.
- External oil leaks at the PTO housing – Deteriorated O-rings or a cracked converter housing lead to visible hydraulic fluid seepage near the bell housing, often mistaken for engine oil leaks.
- Erratic shift cycling – A failing valve body or worn spool valves cause the transmission to hunt between gears or produce harsh, jarring shifts during directional changes.
- Overheating with reduced torque – Internal wear on the torque converter stator or a clogged cooler circuit results in high operating temperatures and a noticeable drop in pushing or lifting power.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number / SKU | 4644.036.040 |
| Assembly Type | Complete Powershift Unit (6-speed) |
| Dry Weight (approx.) | 385 kg (849 lbs) |
| Overall Length | 720 mm |
| Overall Width | 510 mm |
| Overall Height | 580 mm |
| Housing Material | High-strength cast iron (GGG-40) |
| Input Spline | SAE 14T (10/20 DP) |
| OEM Reference | ZF 4644.036.040 (Direct replacement) |
Compatibility
This complete unit is engineered for the ZF WG 201 series, but its mounting pattern and hydraulic logic also allow direct fitment into several adjacent model families. Verified compatible transmissions include:
- ZF WG 180 – Early production models with 6-speed countershafts require adapter plates; this assembly bolts directly to later WG 180 revisions.
- ZF WG 200 – The primary application for this SKU; used in Case 921E and New Holland W190C wheel loaders.
- ZF WG 211 – Limited compatibility with specific torque converter housings; check bell housing bolt pattern (SAE #3).
- ZF 4WG 200 – Some 4-speed variants can be upgraded using this 6-speed assembly with a software flash on the control unit.
Always verify the bell housing flange and output yoke dimensions against your machine’s original transmission before installation.
