I added the Prestone stop leak to mine -- except the instructions said to add the entire bottle. My pump now squeals a lot, and I am wondering if this is a self-correcting part of the processes, or a new problem?

The leak actually began when, on my mechanic's advice, I used ATF in place of steering fluid. I had tried draining all the ATF (with a turkey baster) but I can't seem to get all of it out.
Any thoughts and suggestions would be appreciated.