ervsgal

I have a 2002 Lexus Rx300. Used with one owner before me. A piece fell off the exhaust that caused the auto to shake loudly. My husband was following me & picked it up. Couldn't drive it after the shaking started. Went to Toyota dealer & mechanic said that part needed was over $1200 but I could have that part welded back on if I had my own mechanic. They would only replace the whole exhaust part. So I had it welded on & as soon as I get on the highway the vibration stared agin but not as violent. Still don't want to drive it like that. What else could make this happen. The welded it right where the bracket broke off? Help. Just got it & so far my only ride was on the way home.