Ok, so, I posted some of my mods kind of out of order here.
OBVIOUSLY, my first mod was this bad boy:
Took a few attempts to find the right x-gauge commands to add the transmission temp, air/fuel ratio, and spark-retard. But it's nice to have such diverse instrumentation available.
One of the reasons I really wanted to add the trans temp reading is that I was starting to have issues with no torque-converter lockup when it was really cold out. While I'm still not totally sure that there's nothing wrong with my TC, it did seem correlated to ambient weather temperature. I guess there is some programming logic to keep the TC unlocked to help warm up the transmission, but it was costing me some serious fuel.
The previous owner of my truck was meticulous and dedicated to maintenance, thankfully. So of course he still had the original window sticker. I didn't read it over until after taking the truck home, but much to my delight I saw he optioned the engine block heater! I dug around in the front bumper and sure enough, there was the plug.
Now, if I'm going to go to the trouble of plugging my truck in on a timer to warm the block/coolant, I realized I might as well help the transmission and oil out a little also. So I quickly ordered two of these 150W pad heaters:
Amazon.com: Kat's 24150 150 Watt 4"x 5" Universal Hot Pad Heater: Automotive
So I slapped 'em on the oil pan:
And transmission pan:
Shot of both for context:
Then I got both pad heaters wired in with stock block heater up to a marinco plug in the front bumper:
With a timer set to be on from 3 or 4am-8am I am getting anywhere from 40-60°F above ambient for the trans and coolant (no oil temp gauge yet). Whoo-hoo!
So, not quite "toasty warm", but well above the ~10 degree air we've been having lately. And I am happy to report that the T/C locks up much more readily. Probably somewhere between a 1-2mpg impact from pre-heating before my morning commute. The one time I previously tried letting the truck warm up for 10 minutes on a frigid morning before I drove to work... well, I am too embarrassed to report how bad the fuel economy was. Let's just say... single digits.