Overview
The ZF 6057.018.936 EST 37 A for BP230 is a critical OEM genuine solenoid valve assembly engineered for precise hydraulic control within the BP 230 series automatic transmission. This part, identified by SKU 6057.018.936, modulates oil flow to the clutch packs and shift valves, ensuring smooth gear engagement and consistent torque delivery. It is mounted directly onto the valve body and interfaces with the main TRANSMISSION HOUSING to regulate line pressure. As a direct replacement for worn units, the 6057.018.936 restores shift quality and prevents erratic transmission behavior in heavy-duty commercial vehicles.
Symptoms of Failure
- Delayed or harsh shifting: A failing EST 37 A solenoid causes noticeable lag between gear changes or abrupt engagement, often accompanied by a jolt during acceleration.
- Intermittent gear slippage: Worn internal seals or coil degradation lead to pressure loss, resulting in the transmission slipping out of gear under load, especially on inclines.
- Transmission overheating: When the solenoid fails to regulate oil flow properly, excessive friction generates heat, triggering warning lights or fluid discoloration.
- Erratic shift patterns: The transmission may hunt for gears or fail to upshift at proper RPMs, often accompanied by a check engine light related to solenoid circuit faults.
Technical Specifications
| Specification | Detail |
|---|---|
| Part Number | 6057.018.936 |
| OEM Reference | EST 37 A for BP230 |
| Material | Hardened steel body with brass spool |
| Weight | 0.85 kg (1.87 lbs) |
| Dimensions | 120 mm x 45 mm x 40 mm |
| Operating Pressure | 8–22 bar |
| Coil Resistance | 4.5–5.5 ohms at 20°C |
| Seal Type | Nitrile rubber O-rings |
Compatibility
This solenoid is specifically designed for the ZF BP 230 series, but it also cross-fits into several heavy-duty ZF transmissions that share the same valve body architecture. Compatible models include the WG180, WG200, and WG210 series, as well as earlier iterations of the BP 230. It is frequently replaced alongside the HOUS.FRONT SECT and the HOUSING REAR PART during a full valve body overhaul. For applications using the HOUSING REAR SECTION, verify solenoid orientation to ensure proper fluid routing.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4657101078 | TRANSMISSION HOUSING | Main structural casing for gear sets |
| 4657201166 | HOUS.FRONT SECT | Front section housing torque converter |
| 4657201168 | HOUSING REAR PART | Rear section supporting output shaft |
| 4657298101 | HOUSING REAR SECTION | Alternate rear housing variant |
| 0631306816 | CYLINDRICAL PIN | Alignment pin for housing assembly |
| 0636100801 | CAP SCREW | Fastener for valve body mounting |
| 4656301148 | FIXING PLATE | Secures solenoid to valve body |
| 4657301032 | SCREEN SHEET | Fine mesh filter for hydraulic fluid |
| 4657301033 | SCREEN SHEET | Secondary filter for oil return line |
| 0636100803 | CAP SCREW | High-tensile bolt for housing joint |
Frequently Asked Questions
Q: Can the 6057.018.936 be tested before installation?
A: Yes, measure coil resistance between terminals; it should read 4.5–5.5 ohms. Also apply 12V DC to verify the spool clicks audibly. Replace if resistance is out of spec or no click is heard.
Q: Is this solenoid interchangeable with the EST 37 B variant?
A: No, the EST 37 A (6057.018.936) has a different pressure curve and connector pinout than the B variant. Using the wrong version can cause shift timing errors and potential transmission damage.
Q: What torque should be used for the mounting bolts?
A: Tighten the two M6 bolts to 10 Nm (7.4 ft-lbs) using a torque wrench. Over-tightening can crack the valve body or distort the solenoid housing.
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