All Balls Racing – Driveshafts & U-Joints for Polaris, including the jack shaft bearing and seal kit for the upper shaft on the 2007 Polaris 340 Edge LX, and lower track shaft bearing and seal kits for the 03-06 Polaris 340 Classic, 85-89 Polaris Star 250, 1990 Star 250 and 93-95 StarLite 250. Each kit pairs the bearings with the seals that keep the housing sealed, so one job covers the whole shaft support instead of reusing a tired seal next to a new bearing. Drive and jack shaft bearings on these older sleds live in a wet, gritty environment and see constant side load from track tension. When one dries out you get a growl that rises with track speed, then heat, then a shaft that walks in its bore and eats the bulkhead. Replacing the drive shaft bearing and seal kit restores true shaft alignment so the track runs straight, tension holds and belt-to-chaincase power gets to the snow instead of turning into friction. These Polaris jack shaft kits use sealed bearings rated for the load. Press the bearings in square. Send us your sled model and year and we will confirm the right kit and shaft position before you order.