Eaton Fuller K-4125CL RT Hydraulic Clutch Installation Kit

Product Overview

Genuine Eaton Fuller K-4125CL hydraulic clutch-installation kit for supported RT-series transmissions using the standard RT input shaft and clutch-release yoke. K-4125CL is Eaton’s current replacement for the discontinued K-4125 kit.

Part Number and Supersession

• Current sellable manufacturer part number / SKU: K-4125CL
• Legacy / replaced number: K-4125
• Application class: RT-series, standard input shaft and yoke, hydraulic clutch release

Verified Kit Contents

• 14750 snap ring — quantity 1
• 16980 snap ring — quantity 1
• 20550 front bearing cover — quantity 1
• 5566505 pilot bearing — quantity 1
• 81504 ball bearing — quantity 1
• 85541 clutch-brake disc assembly — quantity 1
• A-7786 clutch-release yoke assembly — quantity 1
• K-3453 gasket kit — quantity 1
• L-2017-01 extended-warranty letter — quantity 1
• L-3092 instruction letter — quantity 1
• S-1659 input shaft — quantity 1
• X-7C-1202M M12 x 1.25 x 40 screw/washer assemblies — quantity 2

Application and Service Notes

Confirm the complete RT transmission model and serial number, S-1659 standard input-shaft configuration, front bearing cover, clutch-release yoke, hydraulic release system, clutch housing, pilot bearing, clutch brake, and existing installation-kit number before ordering. Do not substitute a severe-duty, 1.75-inch input-shaft, FR-series, or mechanical-release kit.

Installation must follow the applicable Eaton transmission and clutch service manuals for input-shaft and bearing-cover service, clutch alignment, release-yoke installation, hydraulic system setup and bleeding, clutch-brake clearance, fastener torque, and final calibration or adjustment.

Please confirm K-4125CL, the RT transmission identification tag, standard S-1659 input shaft, hydraulic release system, and all kit contents before ordering.

Parts Verification and Ordering Notice

Please confirm the existing part number, transmission and clutch identification, input-shaft and release-yoke configuration, dimensions, specifications, kit contents, and application before ordering. Cross-reference numbers, parts catalogs, service manuals, repair manuals, PDF references, and application guides are reference material only and may contain errors, omissions, superseded information, or model-specific differences.

Technical References and OEM Documentation

• Eaton Inforanger — K-4125CL Official Bill of Material
• Eaton Inforanger — RT-Series Catalog Identifying K-4125CL as K-4125 Replacement
• Eaton Download Center — Transmission and Clutch Service Manuals