LFD2037, I may be wrong but I think HL wants you to contact their service department directly for these type questions. The forum is overseen by unpaid volunteers. We all try to help each other but sometimes ya gotta call HL CS. Lippert's phone number is 866-524-7821 & 574-537-8900. At this time, I have the Lippert 1621 HD pin box off my unit, for a few more days. If you want to me to take any measurements for you I would be glad to. In fact, if I remember correctly, one of the HL CS guys used to work for Lippert and is real knowledgeable in this area. Good Luck, Tom