I have a ridiculous coolant leak on my 2.8q and when i went under to look at it it looks as if it was coming through the transmission? how much would that be to fix or is there any kind of way i can do it myself?

Can you see any obvious leaks in the hoses?

If not, it could be the overflow tank or the cap. If the tank and cap have never been replaced, it's time anyway.

i took out the tank and i poured down the hose and it came out like a minute later

why should the tank and cap be replaced? i have 100k on my car and mine is original. should i replace?

Well, it depends if you want to practice "preventative maintenance" or not. You could always wait until they started leaking. If you have 100k miles on the originals, it's only a matter of time.

My original coolant expansion tank started leaking at about 75k miles, and I had it replaced. That replacement tank started leaking this past spring at 123,000k miles. So now I have a new tank & cap, and I also took the opportunity to drain the old coolant and fill it with fresh G12 coolant while I was at it.

It's best to just replace the tank if its at 100k mine just now started leaking I lost a whole tank of coolant in a couple days and you shouldn't pay anymore than $50 to fix it

And I just got to 111k and it started leaking