I had this problem in my 1957 300-C conv. and it was not a problem as you outlined. It was the ball and trunion joint at the transmission end of the dr iveshaft. Gary Hagy Hamburg, PA In a message dated 6/2/2006 9:00:26 A.M. Mountain Standard Time, mocarjoe@xxxxxxx writes: For a car to vibrate at only 20 MPH is a serious problem! I'd start by checking every lug nut on every wheel. Loosen then tighten each one, check rear axle nuts and front hubs for missing cotter pins (clue that the nut has loosened). Next jack the car up and try to shake and move the front wheels. Try to shake the tie rods back and forth, rigorously shake all components of the steering system. I doubt a driveline problem unless the drive shaft is bent, but if no front end problem is found, and wheel nuts are ok put the car so both back wheels are off the ground and start the motor and try to recreate the problem without hazarding a drive in it. You might see a broken transmission mount or hear obvious thudding. Good luck. ------------------------ Yahoo! Groups Sponsor --------------------~--> You can search right from your browser? It's easy and it's free. See how. _Click Here!_ (http://us.click.yahoo.com/_7bhrC/NGxNAA/yQLSAA/8LmulB/TM) --------------------------------------------------------------------~-> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links [Non-text portions of this message have been removed] ------------------------ Yahoo! Groups Sponsor --------------------~--> You can search right from your browser? It's easy and it's free. See how. http://us.click.yahoo.com/_7bhrC/NGxNAA/yQLSAA/8LmulB/TM --------------------------------------------------------------------~-> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/