2002 Toyota Camry Question: how does water gets into a 20002 Toyota Camry automatic transmission's fluid

Thanks for all the reply's. A month ago I had a shop to replace the engine that my kid allow to run out of oil. Everything was great with the replacement engine but the A/C quit working last week (It was changed out during the engine change). The power steering return hose was leaking fluid, and exhaust flex pipe had a leak(which I noticed right after the engine change.) So last week I took it back to the shop. Picked it up Sat after a day in the shop. They fixed all those problems. I checked it out and everything looked great except that it shifted a little hard a couple of times when I was checking it out but I failed to check the Trans fluid because I checked it after the engine change and assumed it was OK.(my mistake). After a couple of days of driving my daughter said she smelt a funny or odd order. I checked it out and this is where I'm at. I also suspect a bad seal is in this mix also. I see evidence of it. Thanks again.

I agree with goodguy , but I won't argue with wetry either. BUT ......a thought did occur to me ( and I got a headache shortly after) is A/T line pressure below 15PSI , if the cooler is bad then it should be transferring A/T fluid to rad. when line pressure exceeds pressure in cooling system, right? OK , I'm going to take some ADVIL.

HI Z,
I AGREE, REASON I ASK ABOUT FLIUD IN COOLANT. A/T PRESSURE IS GREATER THAN RAD.
EXCEPT WHEN ENG. IS OFF.(RESIDUAL PRESSURE IN RAD.)BUT SHOULD BE MIXED IN TRANS. AND RADIATOR BOTH.

Thank you I'm a -DUH_