Updates: "Solved problems & unsolved ones"

For those who have read and or helped me with my milkshake and rad issues, here is the updates:

Eng. Cooling Sys:

ok, new rad installed, flushed engine w/dis. water (6gal total). Replaced the thermostat and gasket. Put almost 3 jugs of napa asian red/pink coolant in. There was like a chocolate milkshake color, not texture but color so i performed two flushes using that prestone cleaner stuff. and also flushed without thermostat installed. I situated the thermostat with the jiggly small thing at 6 o'clock.

Trans:

Replaced trans filter and gasket. B4 that I manually flushed trans with about 32-36qts of trans fluid. Its still not as clear as new fluid but its way way far from looking like how the milkshake was. Here is what I would like to know:

1) If trans uses Dex3(H), can you use this just to/for flushing the bad trans fluid out:

https://www.walmart.com/ip/Multi-ve...-007-1789437688cf03&athancid=null&athena=true

And then when its showing "clean", have it flushed/replaced with fluid that is recommended? Reason I am asking is because of cost and amount. It is easier and more efficient cost and size wise to get a 5gal or more instead of buying the whole shelf at WM. What do you guys think?

Also my drain plug is leaking and noticed upon removal of drain plug that it is stripped. It goes into pan and stays but still drips. Not sure if pan hole is stripped though.

What is the size of the plug anyway?
Is it the same as the oil drain plug?
Could I use a rubber grommet as a temporary fix?

Lastly I noticed that where my brake hard line goes into my drivers side caliper has a slow leak. this is something new. Last year b4 covid, I replaced rotor's, pads, calipers with the larger upgrade but not the biggest ones. Forget what size actually, but you have the factory size, then the size I choose (maybe 199mm?) and then theres the 231mm. Anyway any suggestions as to how to correct the problem or diagnosis it?

thanks in adv brothers

(cross posted)