Thought I'd share what I did yesterday. Both knobs on the stereo were broken so I modeled one and 3D printed replacements. I've attached the solidworks and stl file in case anyone else wants them. I removed the flange so they can be inserted from the front. I did end up having to drill out the shaft hole to 0.136" and I get a good press fit. Works fine. If I cared I could polish them up a bit but I don't.
At the same time, when I had the radio pulled out, I resoldered all the pads relating to the Aux port. There are three pads in one area if memory serves and about 5 pads on the main circuit board. I no longer have problems with my left speaker dropping in and out all the time.