Per my exceedingly long post above I have the transmission out so I could get to the rear main seal. The tranny itself was leaking at least to some degree so I am attempting to do a better job sealing it so I can better tell what oil traces I'm seeing on the underside of the car are engine oil vs MTF.
I had two main objectives here:
-replacing the shifter rod o-rings which I did not do on my first time through
-replacing the gaskets I had put in originally because I had used just general RTV orange gasket maker which has generally proved not up to the task for sealing oil.
Regarding the shift rod o-rings, I elected not to replace anything in this particular assembly when I cleaned up the transmission and replaced all the other seals the first time simply because it seemed pretty complicated. That, and I figured "Hey, it's at the very top of the transmission, how badly could it leak?" However from the "first" drive there's been an oily coating on these shafts and below, so I had to address them this time through.
I'm not going to cover the whole procedure here. The "Buckeye manual" does a pretty good job here, as does this video. Jump to 39:40- https://www.youtube.com/watch?v=30F4P0Vtfow
What I found on some TR6 forums is that instead of the standard o-rings, others were using x-rings in their place. Specifically McMaster-Carr 90025K226: https://www.mcmaster.com/90025K226/. If anyone else wants to go this route I had to order a pack of 100, so just let me know and I can drop some in an envelope for you.
I found a few other things to address along the way. The o-rings are held in place by a plate that sandwiches them between it and the transmission cover. My plate was a bit dinged up and warped, probably not keeping things sealing tight.
Since these are NLA some quick time in the bench vice seemed to get things straightened up pretty well.
The rods themselves had at a minimum some discoloration on them, so I touched them up with some 1500 grit paper to knock down any high spots that have come up.
Down to the nitty gritty. New X-rings in place.
Reassembly is not overly complicated, at least in theory. The shift rods have indentation in them which catch a ball to give a positive location for N/1st/2nd/3rd/4th and R. A spring keeps tension on the balls. One has to compress the spring and send the ball down into the hole which houses it in order to slide the particular shaft past the ball. For the life of me I could not get the ball down far enough, so we went the route described in the Buckeye manual.
The plugs drilled out, and tapped for hardware.
Set screws acquired but even the shortest examples the hardware store had were too long. If I wanted to take more time I likely could've ordered the proper pieces from McMaster as well, but I have a bench grinder so... The proper screw height ended up being about 1/4",
Two screws in the homes.
Shifter action felt proper, so I think we're all good to assemble the rest of the gearbox. I decided to forego the thin paper gaskets one can find for the transmission body sections, which I have to believe are about useless anyway. Instead I used Chrysler transmission/differential silicone sealer. This is applied with no gasket and then assembled to cure.
One other thing I came across on the TR6 forums in folks drilling out the vent holes in the trans case to lessen the likelihood of them getting clogged. I decided I could do better than that. I drilled out a 1/4 hole in the trans extension (prior to assembling extension & trans), fit some air line through it and shmutzed it up with some sealer, then secured the line to a pair of bolts for the extension and voilà, a breather tube.
