What size transmission cooler line adapter do I need for my 1999-2007 Super Duty? ⅜ or ½?

Based on the research done here at Glowshift, due to the different model types and applications, the 1999-2007 truck could have been ordered from the factory some trucks came equipped with ⅜ cooler line and others came with ½ cooler lines. We offer both adapters on our website under a transmission adapter and we highly recommend customers measure the outer diameter of their cooler lines before making any purchases.