Don't bother... if you want to restore your engine, pull it apart and rebuild it.
No amount of oil additive can replace metal that has been worn away after 188,000 miles....
Yeah, on the front face of the housing, there's about 8 bolts holding it on, but they are small, easily undone and rarely sieze.
It's a half moon shaped piece of cast ali, and is removed to allow you to do/undo the torque converter bolts
With it removed you get to see around a quarter of the edge of the ring gear
I did mine just over a year ago, so glad I decided from the outset to do everything, the more you look the worse it gets.....
Most of the problem you will have is finding good steel to weld too, looking at your photos...
Hmmm, you will only ever get about 4.5 litres of oil in an autobox, as you can't drain the torque converter, I hope you didn't top it up with another 9 litres did you?
Good plan on the temp gauge front, will be interesting to see how hot it does run in practice.
Had another thought on the oil level, I am pretty sure you can get rid of the dipstick and just plug the hole in the side of the box, use this hole as the filler level, someone else may be able to confirm... maybe JST IIRC.
Lights, tyres, warning lamps, excessive oil leaks, wheel bearings, steering/suspension joints/bushes, and seat/belt security, fill the washers up and away you go, I think?
Oh, and don't go to a play day beforehand
My guess would be not whilst he has a 5.2 V8 in bits in the same workshop....
That or he doesn't want to ruin the extra performance the 5.2 would give him by making his own out of bits of the Titanic.
You can test them yourself TBH, cleaning isn't REALLY necessary IMHO, other than a squirt of some solvent and cleaning up with a rag.
For testing, put a piece of hose on the injector, then whilst blowing into the tube, put 12V across it. It shouldn't leak when off, and should blow through cleanly when on.
You can test it all plumbed up to a fuel line too, which I have done to see injector spray patterns, but the above test should be sufficient.
Start from cold and allow to idle, foot on the brake and select R, N, D, 3,2,1,2,3,D,N. Pause in each gear for ~10-15 secs, then leaving it in neutral, go check your dipstick.