I can only go by pics that I have seen so here it goes. The 3 Speed with column shifter was 1st avail in a 1/2 ton AD for model year 1948. (47 had 3 speed w floor shifter). The linkage rods on the 48 where it connects to the column is threaded on the end. The "clamps" on a 48 really are not clamps they are actually referred to as "control rod swivel" in the shop manual. The 49-51 linkage rods are not threaded and a newer designed linkage "control rod swivel clamp" was used. Not sure why they changed it but they did. The newer design allows you to loosen the clamp and slide the rod up or down to adjust. The 48 design is threaded so you need to screw the swivel up or down the threads to adjust the rod. I will assume that the 1948 style rods / swivels are pretty rare. I honestly found no information except what is in the shop manual to back this up but I did find a pic from a restored 48 that showed what I am talking about but it is not crystal clear. I guess this is really useless info but figured I would share in case someone was restoring a 48 and wanted it 100%. Please correct me if I am wrong.
