About that 18 gauge wire. I thought about buying some, but I couldn't find connectors for it. It's listed as several hundredths of an inch smaller in OD than the 16 gauge IIRC, I was afraid it wouldn't make a water-tight seal with the 16 gauge connectors.
It's actually a non-issue. Take a look at the wiring diagram a bit more closely...everywhere it calls for 18 AWG for the TCM harness, it doesn't terminate with a typical military or bullet connector. All of it goes directly from the TCM to the transmission stub. If you're wiring based off of transmission repair stub and a TCM stub, you're just going to be splicing wires directly to other wires, so you can just use adhesive-lined heatshrink butt connectors, or solder and heatshrink. It also calls for 18 AWG wire for a short dongle from TPS to engine harness, which just adapts from a weather seal connector on the engine harness to the metri-pack connector on the TPS (and also allows for easy installation of a service cable that has bullet connectors to help with setting the position of the TPS). The metri-pack and weatherpack connectors handle 18 AWG just fine if you buy the appropriate connector. Just as a note, I'm using a civilian TPS on mine that directly has a weather pack connector, so I'm just direct-wiring my harness to it with no dongle. I have extra connectors, so I'm just going to make my own service stub with breakout leads for measurement.
Other things out there again show as a non-issue: STE-ICE Frequency converter, if you install it, is 16 AWG wire. I didn't see a spec listed for the fan cutoff switch, but I'm just going to assume its 16 AWG since there's no special notation and the part isn't in front of me. Best part about the 18 AWG wire is it's a butt-ton cheaper than the 16 AWG wire, if you're trying to follow the type of wire originally used in the application. I think I got a super-overkill spool of 18 AWG wire (500 ft...I used probably 75 feet) for $85 delivered, but 100 measly feet of 16 AWG that just barely gave me enough wire was $28 + shipping. Buy two spools of that 16 AWG wire and you only have 200 ft to show for nearly the some money as 500 ft of 18 AWG.
*EDIT: I've been trying to find
any smaller quantity of that Teflon wire I bought for sale. I can't find any exact match, but the 500 ft spools are still for sale if you search for M22759/1-18-9. The stuff is truly high-quality stuff. It's not actually tinned, but it's silver-plated copper. On top of that, it's laid in a PTFE (teflon) jacket, and then that jacket is wrapped in a fiberglass braid that's also coated with PTFE for further temperature and abrasion resistance.
This was the wire that was rated for 200 C operation, not the CSPE wire like I had thought earlier.