The weather was a bit better than before, so today (Saturday) I got the trans cooler completely plumbed. Wiring is all that's lacking, but most of that is already in place. The fitting that came with the trans cooler temp switch was some kind of flared fitting, so I went old-school and got some brass.
The thermostatic valve from DeRale is mounted with two ¼-20 bolts to a piece of 1/16" x 1½" x 1½" aluminum L channel. The valve has holes for 4 bolts, but the heads are so close that they interfere with each other! Using the instructions (yep, i kin reed!) I marked the raised arrows with magic marker, then added T and C for trans and cooler. They'll wear off eventually, but helped me to install it correctly.
First, I found out which line was pumping fluid TO the cooler by starting the engine briefly. Then I got all the hoses in place as well as a brass Tee for the temp switch. After cinching down the clamps, I started it again. There was 1 leak at the original lines where the new hose was supposedly clamped. I found out that the ends of both lines actually get smaller right at the end, so I slid the hoses further onto the lines and then clamped them there. No leaks after that.
The hoses are in a bit of a tight spot, so I used both pieces of the hose that I was cut off when I shortened the coolant bypass hose a few weeks ago. I just sliced it lengthwise, then zip-tied it around the hoses.
Don't hate on me for using worm-gear clamps on some of the fittings. I used the crush type on half a dozen, but the hose got a bit too big when it went over the barbs, so I had to switch to wormy clamps. I tried re-using the spring clamps that came on the stock trans cooler lines, but the hose is too big for them as well.
After making sure there were no leaks, I cut off the excess lengths of the wormy clamps.