I replaced my 3 speed automatic with an M46. This involved changing out the tranny itself, the flywheel assembly, and the entire drive shaft all the way back to the rear differential. All the parts are from a 1983 244, but I am still using my existing differential and rear axle, as well as the original speedometer cable and instrument cluster. On the previous thread, someone mentioned that there are three sets of drive gears for the speedo cable, depending on which rear axle I have. I'm not quick sure what that means, and why it makes a difference if I have a new drive shaft, but the same axle. Are the speedo cables different in some way? Where is this drive gear for the speedo cable? Thanks!