Nosirrahg thanks for Post 910. I was lazy and did not check earlier posts. Turns out the problem on mine is intermittent. Right now running fine. I went to a reputable independent shop. He said the Impala has had problems with the pressure control module. He also said without a check engine light and no symptoms he would not recommend doing anything. Did you get a check engine light? I went to a Chev dealer. The Service Tech said that there were no such problems with the Impala transmission. If anyone knows the number of the technical bulletin I would like to take it to the dealer. Thanks.