Hello newb here and not sure if posting correctly. My apologies in advance. I have a 2009 Chevy Tahoe LS Sport 4.8l . While driving my transmission lost 3rd. Then ask gears. It was a leaky pass through connector. In replaced that then went for test run. Everything was going great then lost 3rd on up. Thought it was shift solenoid or pressure solenoid. So i bought complete master solenoid replacement kit and harness. After install i still do not have past second gear. Could it be the TCM or what could be the issue?