#1: I have a '96 V6 with 101k miles, and has made the whining noise sinc eI got it at 61k. Shouch just be normal. but it also depends on what kind of noise it is exactly. Is it just an extremely high pitch? Thats what mine is.
#2: It;s good practice to regularly drain and refill the tranny pan. It;s not hard, and will only cost you like $10 in tranny fluid.

May as well just do it. And at 123k miles, if it;s not burnt, it's likely been changed.
#3: Several places. Check:
-Here on TN in the classifieds
-Ebay
-www.car-part.com whiuch is a hugh salvageyard database
-Find (If there is one around) a Pick and Pull junkyard where you pull the parts off the car yourself.
Ebay may be the best bet though.
#4: As poiter said, the Gas and Trunk are 2 seperate cables. Since you hear the clicking in the trunk, that is where the issue likely lies. I;d suggest taking off the trunk locking mechanism and inspecting it to see if something is wrong.
I hope this helps a little,
Adam