I tried for 3 hours last night to coax the shift coupler off the tranny shifter shaft with no luck. It will move about a cm after removing the conical screw but won't come off. Any suggestions?

 

Take off the front shifter ball cup so your not trying to push into the splines on the shifter shaft.
Assuming you haven't done this already.

 

Get a helper.
Helper shifts to second.
You grab transmission shaft w/Visegrips.
Helper puts pressure on toward third, while you hold shaft back in transmission and pry between the coupler and Visegrip w/screwdriver.

 

OK it's off. Thanks for the tip! Do the bushings look too worn to use? There's a little slop but they are not broken. Are they available as replacement parts? My goal is to replace the rubber dust boot. Anyone BTDT? Obviously the small corrugated end goes on first, then the joint. But I can't compress the boot enough nor can I stretch it over the joint? Any tricks?

 

actually we have the same problem with the 1980 931, or the 1979 924, what I always did was just to remove the bolt that you have removed and lightly put it into 3rd gear, then once in ger, slam the shifter forward, it normally breaks it loose, it sounds harder on things than it is, I didn't like the vice grip approach as it can damage the shaft and there is a seal on that shaft that holds tranny fluid in.

 

Looks like what was binding things up was the wallowed out set screw hole in the tranny shaft - a bit deformed - probably from the set screw being loose. A little filing will fix that. I will use loctite when re-installing the set screw. I may have to cut the new rubber dust boot to get it over the joint and re-glue it unless someone has a method for this.