Transmission on 2006 Hummer H3

I Have a Hummer 06 2006, and its has some issues in shift when its hot, it takes too long to, and even with 6000 RPM it doesnt change to the next gear. In the morning it behaves good but when hot it begins. what should I Do or Change? Peterson

Asked by for the 2006 Hummer H3
The computer controls the transmission. It needs to be diagnosised by a pro.
Thank you very much.