ZF 4663.301.026 COVER | OEM Genuine Part

Overview

The ZF 4663.301.026 COVER is a critical sealing and protective component within the final drive or PTO (Power Take-Off) housing of heavy-duty construction machinery transmissions. This OEM genuine part, identified by SKU 4663.301.026, mounts directly onto the transmission housing to shield internal gears, bearings, and clutches from external contaminants such as mud, dust, and water ingress. It also serves as a structural mounting point for ancillary sensors and plugs. In the assembly sequence, this cover is secured after the 4663101003: HOUSING is installed, and it is fastened using 0636100817: CAP SCREW hardware. The cover’s precise fit ensures proper oil retention and maintains the hydraulic pressure necessary for smooth gear engagement in demanding off-road applications.

Symptoms of Failure

When the ZF 4663.301.026 cover degrades or is damaged, operators will notice distinct operational issues. Look for these specific failure symptoms to diagnose a worn cover:

• External oil seepage around the PTO housing: A cracked or warped cover allows transmission fluid to escape, often visible as wet streaks on the bell housing.
• Contaminant ingress leading to gear whine: If the cover seal fails, dirt enters the transmission, causing premature bearing wear and a high-pitched whining noise during operation.
• Intermittent clutch slip in low gears: A compromised cover can cause a drop in hydraulic pressure, resulting in delayed engagement or slipping when the machine is under heavy load.
• Vibration at the mounting flange: Loose or broken fasteners, often related to a deformed cover, produce noticeable vibration through the chassis during acceleration.

Technical Specifications

Compatibility

This cover is engineered for ZF’s heavy-duty powershift transmission series commonly used in wheel loaders, graders, and dump trucks. It is a direct fit for the following transmission models:

• ZF WG180 (all variants)
• ZF WG200 (Series 2 and 3)
• ZF WG310 (early production)
• ZF 4WG-200 (with PTO adapter)

During installation, ensure the 0631306816: CYLINDRICAL PIN is correctly aligned to prevent cover rotation, and use a new 4656301148: FIXING PLATE to lock the cap screws in place. Always replace the sealing O-rings when servicing this cover.

Related Components