Excellent! The diameter of the groove on the upper shift rod is almost exactly the same as the inner diameter of the plastic sleeve on a 10-12 AWG butt connector (standard yellow plastic one). The plastic sleeve even has a bit of a flare at the ends. I drove out the inner metal crimp part so I had just the plastic sleeve. Then cut a section of the plastic tube the same length as the groove on the shift rod, with part of the center non-flared section and par of the flared end section. That gave me a sort of cone-shaped plastic tube. Cut a slit wide longitudinally to allow it to slip over the shaft, and it works like a charm. I'll follow up with a few pics just in case anybody else finds themselves in this situation.
Thanks, travjenkins. I owe you a beer!
Lewis