Speedometer is driving me crazy- Something is Wrong

There are a number of gear diameters. If you look at the housing the gear goes in, the speedo gear is off set to accommodate different gear sizes. there are numbers around the rim of the housing that correspond with number of teeth on the gear and a nub on the transmission that acts as a pointer. You have to loosen the speedo cable nut on the housing to be able to rotate the housing.
Yup, I finally got it to go. The o-ring I had wasn’t the right one. Put the old o-ring back on and it slipped right in.