I know there is a similar post about this, but my problem seems a little bit different. Last night I was at a red light and it was in first (Automatic) and it started to slip and quickly grabbed and then felt like it was going over small bumps like the transmission was grinding. It now does this through 1st, 2nd, and 3rd will slip into 4th roughly. The fluid is perfect. Could it be the valve body, or do you suggest that I need a AOD rebuild?