The TeraFlex Low300 heavy duty output kit replaces the stock output shaft of the Dana 300 transfer case (1981-86) with a heavy-duty output shaft. The new shaft is better suited for high-torque and high-stress situations because it is thicker and stronger. It is great when combined with the Low300 gear set because of its additional strength. Note: This kit is designed to be used on the Dana 300 transfer cases that originally had the longer tail housing. Bolt pattern differences prevent this kit from working with the shorter tail housing design. This kit does NOT fit 1980 models.