Overview
The ZF 0501.211.526 PUMP is a critical hydraulic component engineered specifically for the WG 98 Series transmission family. This OEM genuine part serves as the primary fluid mover, generating the necessary oil pressure to actuate clutch packs, lubricate planetary gearsets, and maintain thermal stability within the transmission housing. Positioned within the pump drive assembly, the 0501.211.526 draws transmission fluid from the sump via the SUCTION TUBE and delivers it under pressure to the valve body and torque converter. As a direct replacement unit, this pump ensures consistent volumetric efficiency and reliable hydraulic output for demanding industrial applications.
Symptoms of Failure
- Low hydraulic pressure and gear slipping under load — When the 0501.211.526 pump wears, internal clearances increase, causing pressure drop. Operators may notice delayed engagement or slipping during acceleration, especially when the transmission is hot.
- Whining or cavitation noise from the transmission — A worn pump often produces a high-pitched whine or rattling sound, particularly at idle or low RPM. This indicates air entrainment or insufficient fluid supply through the suction circuit.
- Erratic shifting and harsh clutch engagement — Inconsistent pump output leads to fluctuating line pressure, resulting in harsh or unpredictable shifts. This symptom is often misdiagnosed as a valve body issue when the root cause is the pump itself.
- Visible oil leaks around the pump mounting area — Degraded seals or a cracked pump housing can cause fluid to weep past the O-RING or O-RING interfaces, leading to low fluid levels and eventual transmission overheating.
Technical Specifications
| Specification | Value |
|---|---|
| Part Number | 0501.211.526 |
| OEM Reference | ZF 0501.211.526 |
| Material | Aluminum alloy housing with hardened steel gears |
| Weight | 2.85 kg (6.28 lbs) |
| Overall Dimensions | 180 mm x 120 mm x 95 mm |
| Displacement | 18.5 cc/rev |
| Maximum Pressure | 22 bar (320 psi) |
| Mounting Type | Flange-mounted with CAP SCREW fasteners |
Compatibility
This pump is designed for the ZF WG 98 Series, which includes the following transmission models: WG98, WG120, WG150, WG180, and WG200. It is also compatible with select variants of the WG 80 Series used in off-highway vehicles and material handling equipment. The 0501.211.526 pump interfaces directly with the TRANSMISSION HOUSING and the HOUSING II assembly. Always verify the TYPE PLATE on your transmission to confirm model and serial number before ordering. The pump is secured in place using a CYLINDRICAL PIN for precise alignment.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4660101015 | TRANSMISSION HOUSING | Main structural casing for gear train and valve body |
| 4660301054 | HOUSING II | Intermediate housing supporting pump and clutch assembly |
| 0631306174 | CYLINDRICAL PIN | Alignment dowel for pump-to-housing positioning |
| 0769123894 | TYPE PLATE | Identification plate with model and serial number |
| 0750100022 | SCREW PLUG | Seals hydraulic test ports and drain passages |
| 4660221029 | SUCTION TUBE | Transports fluid from sump to pump inlet |
| 0634100317 | O-RING | Seals pump-to-housing interface |
| 0636103273 | CAP SCREW | Fastens pump flange to transmission housing |
| 0634306311 | O-RING | Seals suction tube connection |
| 4660321029 | FIXING PLATE | Retains pump and prevents axial movement |
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