Overview
The ZF 4644.026.312 WENDEGETRIEBE Powershift Transmission Assembly is a complete, factory-sealed unit engineered for heavy-duty industrial drivelines. As a core component of the ZF WG 200 Series, this assembly integrates the forward-reverse shuttle clutch, planetary gear set, and hydraulic control valve body into a single, ready-to-install package. The SKU 4644.026.312 specifically denotes a full replacement assembly, eliminating the need for piecemeal repairs. This unit manages torque distribution and directional changes under load, making it critical for wheel loaders, forklifts, and telehandlers operating in demanding environments. Its “WENDEGETRIEBE” designation confirms its shuttle-shift capability, allowing seamless direction changes without clutching.
Symptoms of Failure
When the ZF 4644.026.312 assembly begins to degrade, operators will notice distinct performance issues. Delayed engagement when shifting from forward to reverse is a primary indicator, often accompanied by a harsh “clunk” as the clutch packs struggle to lock. Hydraulic oil leaks around the bell housing or shift cylinder seals are common as internal O-rings harden and crack. Another frequent failure mode is intermittent gear slipping under heavy load, where the transmission momentarily loses torque transfer during acceleration. Finally, contaminated transmission fluid with metallic particles signals advanced wear in the planetary gear bearings or clutch friction plates, requiring immediate replacement of the complete assembly.
Technical Specifications
| Specification | Value |
|---|---|
| Assembly Type | Complete Powershift WENDEGETRIEBE Unit |
| OEM Reference | ZF 4644.026.312 |
| Overall Length | 485 mm (19.1 in) |
| Dry Weight | 68 kg (150 lbs) |
| Housing Material | High-Strength Cast Iron (GGG-40) |
| Input Spline Count | 14-tooth, 2.5-module |
| Max Input Torque | 620 Nm (457 lb-ft) |
| Hydraulic Pressure Range | 14–18 bar (203–261 psi) |
Compatibility
This assembly is specifically designed for the ZF WG 200 Series transmission family. It directly replaces units in the following models:
- ZF WG 180 (late production variants with 14-spline input)
- ZF WG 200 (all standard configurations)
- ZF WG 210 (when equipped with the 4644 prefix housing)
- ZF 4WG-200 (four-speed powershift versions)
Always verify the input flange and shift cylinder orientation before installation. This unit is not backward-compatible with the earlier WG 150 series without adapter plates.
Installation Notes
Ensure the hydraulic control valve is calibrated to the WG 200 series pressure curve. Use only ZF-approved Dexron III or equivalent transmission fluid. Torque all M12 housing bolts to 85 Nm (63 lb-ft) in a cross-pattern sequence.
