The A 179854 Fourth Gear is a HSAtransmission component designed for the transaxle mainshaft of Case backhoe loaders. This gear is responsible for transmitting power in fourth gear, ensuring smooth speed transition, stable torque delivery, and reliable machine operation.
Manufactured to strict HSA standards, this gear features precision-machined teeth and high-strength heat-treated steel, providing excellent resistance to wear, shock load, and continuous operation in demanding construction environments.
This component is installed on the transaxle mainshaft and is identified as Photo No. 25 in the transmission exploded parts diagram. It is a direct replacement for worn or damaged gears and is essential for restoring proper transmission performance.
HSA fourth gear
Designed for transaxle mainshaft application
Precision gear teeth for smooth power transmission
High-strength, heat-treated steel construction
Excellent durability under heavy-duty operation
Direct OEM replacement
Case 580 E
Case 580 Super E
Case 580 K
Part Number: A 179854
Product Name: Gear – Fourth
Location: Transaxle Mainshaft
Photo Reference: No. 25
System: Transmission / Transaxle
Brand: HSA
Used in manual transmission transaxle assembly
Recommended to inspect bearings, synchro rings, and adjacent gears during replacement
Proper alignment and lubrication required during installation
（图示编号：25）
A 179854 四档齿轮 是用于 Case 挖掘装载机变速箱 / 变速桥主轴（Transaxle Mainshaft） 的 HSA。该齿轮负责第四档动力传输，确保换挡顺畅、动力输出稳定，并维持整机正常行驶性能。
产品采用高强度热处理钢材制造，齿形精密加工，具有优异的耐磨性与抗冲击能力，适合建筑工地等高负荷作业环境。
该齿轮在变速箱分解图中标示为 图号 25（Photo No. 25），可直接替换磨损或损坏的原有齿轮。
HSA 四档齿轮
安装于变速桥主轴（Transaxle Mainshaft）
齿形精准，动力传输平稳
高强度耐磨材质，使用寿命长
原厂规格，直接替换
Case 580 E
Case 580 Super E
Case 580 K
零件号： A 179854
名称： 四档齿轮
安装位置： 变速桥主轴
图示编号： 25
系统分类： 变速箱 / 变速桥
品牌： HSA
用于手动变速箱系统
更换时建议检查轴承、同步器及相邻齿轮
安装需确保润滑与正确对位
