Shift linkage location

Being a 77 it will have either the column shift or a floor shift, depending on options. The floor shift just has the lever through the floor and a rod up to the side of the transmission. The column shift has a longer rod that goes next to the steering column and exits out at the bottom of the firewall, from there a rod goes down to a rockshaft mounted between the engine and the front subframe. From that rockshaft back to the side of the transmission will be another rod which moves the lever on the transmission lever to select the gearing.
What issue are you having? The only places they normally have issues are at the bushings in the linkage points that wear and then the linkage gets sloppy. Most of them are very simple to replace and if you apply some silicone grease to them they will last a very long time.