I recently had my whole engine taken apart and cleaned since the pervious owner before me had somebody fiddle with the front cover and all my seals were broken for my coolant line leaking into my oil pan. But now whenever i shift my engine will shake for 20-30 seconds then stop, also my check engine light came on. Is the sign of a bad transmission mount? Or is it my transmission going? I'm in college right now so all my tools are at home, so my ability to check certain things are going to be limited. Thanks in advance for everybody's help!