Had a warm temperature shift issue, need some help!

First, thanks to all who responded to my recent brake adjusting issue...problem solved!  New issue, I rode in a local Memorial Day parade today and the van was a big hit, thousands of cheers....as the parade went on, temp gauge started to rise after 20 mins of stop and go, showed 220-230 but no boil over from cap, usually runs 190-195 on warm days (who knows how accurate a Sunpro Guage is?)...the problem occurred when as it got hot, it started to pop out of 1st gear and eventually I could not shift into 1st or reverse, but 2nd and 3rd worked fine and I drove it using only 2nd and 3 until I got her home...after it cooled about 10 minutes, the shifter freed up and it shifted fine on a test drive??  Since 2 and 3 worked fine, I don't think it was the clutch, trans or throw out bearing heating up causing hard shifting?  The only thing I can think of is that the 1-R shift rod that is closest to the radiator heated up and expands or warps?  could that be?  I shortened the adjuster a little and it still shifts fine, thinking if the rod expanded it would not let the shifter seat into position but its seamed like it was jamming and then cleared as soon as the engine temp went down...as for the running hot in the first place, I will do the usual, flush and replace with new proper 50/50 coolant, I have no idea what the PO put in there other than a 190 thermostat and green coolant!, I'll look into a pusher electric fan if still needed, etc...radiator looks original but is in great condition and could be boiled out if flush isn't enough, but any thoughts on the high temp shift freeze up appreciated! Thanks in advance...

Parades are a lot of fun ! And also a good testing ground for the cooling system at slow speeds. The fan has to do all the work. You might be on to something with the shifting rod. Usually the bushings are worn out enough probably to overcome some change in length but if you have everything snugged up and it was adjusted close perhaps it could do that? Stat temps are mostly open to opinion. 190 for a six seems a little high. To me (opinion inserted) 160's are for tractors. It's pretty nice to have decent temps come out of the heater and defrosters. Is it running the 4 blade fan yet?
You got it looking really nice ! I run sunpro gauges, they are pretty accurate so far.

Its running a five blade fan and I think I will change the stat to a lower one, I get super heat now with the valve open but I won't be using the van much in the winter here. New front bushings and rears are fairly tight, no bind at the guide slots, have greased plastic wire mold over the edges...I'm think the gauge is accurate because in stays right on 190 in cooler weather which matches the thermostat in there....