Overview
This ZF 4681.034.005 CONVERTER BASICPOWER Transmission Assembly represents a critical torque multiplication component engineered for heavy-duty driveline applications. Positioned between the engine flywheel and the planetary gearset, this complete unit converts rotational energy into hydraulic force, enabling smooth power transfer under extreme load conditions. The SKU 4681.034.005 is a factory-sealed assembly that integrates the impeller, turbine, stator, and lock-up clutch into a single, pre-balanced module. Designed for direct replacement, this converter eliminates the need for internal disassembly, reducing downtime during transmission overhauls. It is a core element within the BASICPOWER series, ensuring consistent torque curve management for vocational vehicles operating in demanding environments.
Symptoms of Failure
When the ZF 4681.034.005 converter begins to degrade, operators typically notice distinct performance anomalies. Recognizing these signs early can prevent secondary damage to the transmission.
- Torque converter shudder on takeoff: A pronounced vibration or shudder during initial acceleration from a stop, often worsening under heavy load, indicates worn clutch friction surfaces or degraded damper springs.
- Delayed or harsh lock-up engagement: If the converter clutch engages with a noticeable jolt or fails to lock up until higher RPMs, the hydraulic control circuits within the unit are likely compromised.
- Transmission fluid overheating: A failing converter generates excessive heat due to internal slippage. Dashboard temperature warnings or burnt-smelling fluid are strong indicators of stator or bearing failure.
- Low stall speed or engine flare: When the engine RPMs rise significantly higher than normal before the vehicle moves, the converter is no longer efficiently multiplying torque, often due to worn turbine splines.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number / SKU | 4681.034.005 |
| Assembly Type | Complete Converter Unit (Impeller, Turbine, Stator, Lock-Up Clutch) |
| Overall Diameter | Approx. 340 mm (13.4 in) |
| Overall Length | Approx. 210 mm (8.3 in) |
| Pilot Diameter | Approx. 50 mm (1.97 in) |
| Mounting Bolt Pattern | 6-bolt, 180 mm BCD |
| Dry Weight | Approx. 18.5 kg (40.8 lbs) |
| Primary Material | High-strength steel housing with aluminum alloy impeller |
| OEM Reference | ZF 4681.034.005 (OEM direct) |
| Fluid Type | ZF LifeguardFluid 8 or equivalent Dexron VI |
Compatibility
This converter assembly is specifically engineered for the ZF BASICPOWER transmission family. It is a direct fit for the BP 210 Series and BP 230 Series models, which are commonly found in mid-range buses, fire trucks, and construction vehicles. Based on its torque capacity and mounting geometry, the 4681.034.005 unit is also compatible with the following ZF transmission platforms:
- ZF WG180 (all variants)
- ZF WG200 (late production)
- ZF Ecomat 4 HP 500/590 (retrofit applications)
- ZF Ecolife 6AP 1200B (with adapter kit)
Always verify the bellhousing pattern and flexplate bolt circle before installation. This unit is not intended for use with the ZF AS Tronic series or manual transmission applications.
