Here's my thread on the rebuild of the trans linkage. Doing this, and putting a bushing in the shift lever linkage like previous referenced, took nearly all the play out of the linkage - feels great!
--------------------------------------
While I had everything out, I went through the rear shifter linkage in my car. I had a few linkages around - these are pretty common as they get taken off blown transmissions or spare transmissions. I found some interesting stuff. Like everything else, the parts vary in condition. What's interesting is that the linkage arms that were visibly corroded on the outside (like they were exposed to a lot of salt), also had worn pins, while the ones that were not, had good hardware. This seemed to correlate more than mileage.
If the outside of your mechanism looks like the one on the left:
Then the shift pin may be galled like the one on the left in this picture. The one on the right cleaned up nicely with some scotchbrite & fit tight with no play.
Another shot where you can see the top pin is tapered & galled some vs the bottom one, which has nice square edges, and minimal pitting (lloks worse in the picture than after it was cleaned up)
So look around for arms that are clean, their associated hardware should be as well. This should help in sourcing good used hardware. Don't forget to put a new M8 nylock nut on there as well when you're done, and re-install the c-clip:
Doing this removed all the play from the rear mechanism, and only required mixing and matching part from my original trans and another blown trans that I had bought for it's LSD. You could also take the mechanism off of any spare trans you have, as you only nee one good shifter mechanism.