Clutch Steel Plate 2.0mm — OEM 1E6B30-55110 for Yanmar Harvester Transmission

The 1E6B30-55110 is a 2.0mm-thick steel clutch plate for Yanmar combine harvester transmissions, specifically the AW82 and AW85 series. In a harvester multi-plate clutch pack, the steel plates (also called separator plates) are interleaved between the friction plates — when the clutch piston applies hydraulic pressure, the alternating friction and steel plates are compressed together, and the steel plates transfer torque through their splined inner diameter to the clutch hub. This plate is manufactured from high-carbon spring steel (SK5 equivalent) with a surface flatness tolerance of 0.05mm across the plate diameter and a surface roughness of Ra 0.8-1.2 microns — the controlled surface roughness is critical because it provides the correct friction coefficient against the adjacent friction plate material (typically a paper-based or sintered bronze friction material). A steel plate that has been polished smooth by extended slipping (Ra 2.0 microns) will accelerate friction material wear by 3-5x.

Steel clutch plates in a harvester transmission should always be replaced as a complete set — mixing new plates with used plates of different thickness creates uneven clutch pack stack height, which alters the piston travel distance and changes the clutch engagement timing relative to other clutch packs in the transmission. The 2.0mm nominal thickness has a tolerance of ±0.03mm; plates below 1.94mm (worn) or above 2.06mm (from heat warping) must be replaced. Before installation, check each new plate for flatness on a surface plate using a 0.05mm feeler gauge — a warped plate will cause the clutch pack to drag during open (disengaged) operation, generating heat that warps adjacent plates in a cascade failure. The steel plates must be soaked in the transmission’s specified fluid for a minimum of 30 minutes before assembly — installing dry plates will cause immediate friction material transfer (adhesive wear) on the first clutch engagement. Common failure symptoms: clutch pack slipping under load with normal hydraulic pressure (worn plate thickness below minimum specification), transmission oil appearing dark within 50 hours of a clutch rebuild (overheated steel plates transferring heat to the oil), and a metallic “squeal” during clutch engagement (fretting corrosion between steel plate splines and the clutch hub from vibration during disengaged operation).

This steel plate fits Yanmar AW82 and AW85 combine harvester transmissions. Verify OEM number 1E6B30-55110 and plate thickness (2.0mm) on your transmission parts catalog. For related harvester transmission components, visit our Forklift Hydraulic Transmission section.

Technical Specifications

• Part Number: 1E6B30-55110
• Plate Type: Steel Separator Plate, 2.0mm Thickness
• Material: SK5 High-Carbon Spring Steel
• Surface Flatness: 0.05mm Max
• Surface Roughness: Ra 0.8-1.2 Microns
• Application: Yanmar AW82, AW85 Harvesters

Compatible Harvester Models

Each plate is inspected for thickness and surface flatness, packed in rust-preventive oiled paper, and ships within 1-2 business days. 12-month warranty. Browse our Forklift Hydraulic Transmission catalog.