There were red flags that convinced him to stop coaching.
She needed to listen to one voice according to the Russian.
Tursunov said he felt like there would be problems later.
They won eight of 15 matches together.
"We didn't agree on the terms and there were some red flags that just couldn't be ignored," 39-year-old Tursunov told tennismajors.com.
She is a two-and-a-half year project. Her game isn't very polished.
It's going to take some time, but I told her that she needed to have one voice and that everyone on her team should do the same.
It was the first time in the Open era that a British woman had won a Grand Slam.
A full-time coach has not been found since the departure of German Torben Beltz earlier this year.
After losing in the second round at Wimbledon, she started working with Tursunov on a part-time basis.
The trial with Tursunov was supposed to be over after the US Open, but they stayed together for another month.
Since her US Open victory she has not been on the tour.
Tursunov said that he could have stuck around and agreed on everything the team proposed, but that it was not the right thing to do.
Tursunov said that she's a hard worker and doesn't act like she's a superstar. She loves tennis and wants to improve. It's a rare combo.
I wanted to make it work so I worked with her. I had to walk away from a player that I liked and respected.
It was going to be interesting. We just couldn't agree on the terms so I had to leave.
Raducanu has been contacted by the BBC.
She will be leading the Great Britain team in the finals of the King Cup.