well...you said the front trans mount was bad...so i'd start with that. i know mine is broken on one side but it doesn't shake at all. but i don't know how you drive your car, so it's hard to say. i don't beat on mine only b/c i know my front tranny mount is missing the left half of where the nut goes in. napa auto parts is usually really good with carrying what we need. let us know what you find out, either way!