So wait - it overheated AND you lost "power" - what does that mean exactly?
Full story please.
The overheating was separate from the loss of power, but i'm sure it contributed in some way.
on like day 5 of a cross country trip the trans started throwing an overheat warning on the dashboard (the light) it only started in the afternoon when the reflection off the blacktop was throwing a lot of heat towards the trans...so i'd ride the truck 30 or 40 miles at about 46-47 MPH and when the light came on i'd pull to the side and do some studying, the plan being to limp it to a mechanic who is good with transmission stuff...i didn't quite get that far because as i was parking for the night (it had been at least an hour since the last overheat warning) i went to pull a "T" turn (the bigger truck version of a u-turn). and when i hit reverse it just didn't go into gear...luckily i was already on a hill so i used the truck's momentum to coast into the motel's downhill parking area. it threw code 5517, and 22(something). the "T" turn drive to reverse switch would not have been violent in any way i was already fully stopped if not drifting slightly towards reverse.
As noted by several other members, the downshift from 4 to 3 and 3 to 2 was always pretty clunky/tha-chunk-ey...so i had already been kicking it into neutral if i was going into third or lower and then hitting drive once fully stopped...the re-engage while stopped at at idle is much less harsh than the downshift...although i think some folx's hard shift problems have to do with the engine not returning to idle...or being in warm up mode...my shifts smoothed out a lot after i fixed the low idle speed.
Currently it does look like the torque converter might be spinning (it registers a speed for a minute when in gear) but nothing else, no pressure, no "tha-chunk" when you put it into gear. When you try the trans registers whatever gear you selected as having been selected (pick one, i tried them all) but then when you push the pedal down the speedo goes up for a second like you're in gear and then the trans realizes it's not in gear and removes the "you are currently in this gear" number on the selector. I checked all the wiring i could get to and cleaned the connections out with some PB blaster but the guy who had this before me must have re-done some of the wiring because all the connections were in pristine condition, and the wiring itself looks okay-ish (like it'll get replaced somewhere down the road but there's no wire shielding falling off or places where you can see copper near connectors etc. (at some point down the road i'm going to work on the electrical with my dad, a super smart electrical engineer/inventor and veitnam vet, it'll be good quality time).
I've always been a manual trans guy, most of my trucks had 18 speeds in them, a few had 36 or more gears, and if i knew of a way to trade the automatic for a regular big rig 9 speed or something similar i'd do that in a heartbeat, but i suspect if the problem is that it needs a new trans it'll just be easier to throw on a re-manufactured one, they don't look super expensive, the truck and frame all look really good, so it's all a long term investment.
I'm going to grab a small uhaul and a few things out of the truck and the folx at the shop where it is have said they will throw some boat shrink wrap over my already pretty good tarp job and we can start deciding what to do going forward but the vehicle will be okay where it is until they have the time to work on it. i already brought all my really critical things home in my first run in my 2003 jeep rubicon, so i don't "need" anything that's in the LMTV it's all just good quality stuff, like a decent collection of hardwood furniture the dumb undergrad kids throw out at the end of every school year and stuff like that.