Hey I just found out I have a problem with my tranny. p0745- pressure control solenoid A...

I had just had my spark plugs changed and when they were going in, they said a hose that goes to the radiator had broke on them and they were going to put it back together best they can. After getting my car back, I noticed I did not have any heat. So thefirst thing I did was check the coolant and it was empty. So I added some and I had heat for the next week. I then noticed a week later that it was not coming out hot and when I did have the heat on, my car temp would rise and go to "h" (hot). It would then go back down when I shut the heat off. I again checked the coolant and could see nothing so I added some more. Later that week, I then put the car in drive "d", and it did not go. It took a minute or two and then it jumped forward "caught" and then its fine afterwards. It does it all the time.So the next day I immediately took it back to where I had it fixed and they said that that piece they fixed had broke again and it leaked coolant. But he said that the tranny problem has nothing to do with what they did. If Im not mistaken, doesn't the tranny line run through the radiator to stay cool? If there was no coolant, couldn't that line get real hot and burn up the fluid which would then cause problems..(thickening and blackening of the fluid?)...Please advise....Is it possible that it might be tied in with what happened at the repair shop? What things can cause that to go bad?Any info or advise would be greatly appreciated. Thanks, Justin