“Gerrard proved to be very different from what I believed he would be," the Nigerian forward told The Sunday Post.
“I wasn't sure it was the right thing to do. But he kept arguing it would be good for me and my career. Then it was Steven Gerrard himself who convinced me.
“He phoned me three or four times, complimenting me and saying he'd back me to be a success. It made me feel important and convinced me to agree to the loan switch.
“At that point, I knew the club the same way football fans all over the world know Rangers – for its history and the passion of its fans.
“But when I arrived, I didn't even have any time to settle down before they brought in another striker, Kyle Lafferty. That was when the problems started, and my situation soon degenerated into a real nightmare."
“All of a sudden, I was told that I could not use the first-team dressing-room any more. Instead I had to go change with the kids. Then, after a few days, I was also forbidden to park my car inside the training centre.
“I felt humiliated and kept asking what was the reason for the change of attitude. But I never received any answers. Gerrard wouldn't give any explanation about it, neither to me nor my representatives.
“I believe absolutely that I was not given a fair chance to show what I can do. They made me feel like a stranger.
“I started only once (in the League Cup semi-final against Aberdeen) and that was when there were no other strikers available.
“As I say, for me everything went wrong after they brought in another striker (Lafferty).
“Once I put a 'like' on Instagram to a post from a fan – and I was fined £20,000, which was absurd. And Rangers didn't even pay me up everything I was due. They still have to give me my salary for December."
He added: "When it ended, Steven Gerrard didn't even have the courage to talk to me and tell me what was happening face-to-face.
“That was a surprise to me. I didn't expect such behaviour. How he will do long-term as a manager, I do not know. That is his business and I have my own career to think about."