This leading bevel gear oil seal is the critical sealing component installed at the input shaft of FAW heavy truck rear axle reducer, also known as pinion shaft oil seal. It is designed for Euro 4 and Euro 5 emission standard heavy-duty models, used to retain rear axle gear oil inside the drive axle housing to prevent oil leakage, while blocking mud, water and abrasive dust from invading the gear meshing zone and protecting differential and bevel gears. It adopts high temperature resistant fluororubber sealing lip integrated with reinforced metal skeleton. With dual-lip sealing structure, it can endure continuous heavy load, high rotational speed, strong vibration and wide temperature fluctuation in long-distance transportation. Precision spring loaded lip maintains stable contact pressure with rotating shaft, minimizing friction heat and extending service life. Every oil seal passes strict sealing performance test and accelerated aging inspection before delivery. It effectively solves rear axle oil seepage, gear oil contamination and premature gear wear problems, serving as essential replacement spare part for FAW rear axle overhaul for Euro4 & Euro5 trucks.