I have been working near the biggest Napa parts store/warehouse that I've ever encountered & they have many different gear boxes on stock. My truck has a 4 1/4 turn box & I want to upgrade it to the 3 turn like my friend has. I need to find a part# for a 3 turn box, but it has to have a 5/8" input shaft....most 3 turn boxes have the 3/4" input. What works? Please help....I'd like to buy this tomorrow [Thursday].