Okay, sometimes when i'm driving, and only between 35~50MPH, my steering wheel starts to rattle/shake and you can feel it in the whole dash. The car is a 71 auto mav, if it matters. I jacked the car into the air and checked my steering/suspension and everything is nice and tight. It is strange because it is intermittent and only at speed, and only started a few days ago. I got my front wheels re balanced and it made no difference.
Sounds like a possible tire seperation. It could also be a caster angle that moves under road force/load. Could be a number of things. How do the rod bushings look?
Had the exact thing happen on my son's 72 Comet. Ended up being the transmission mount. I would check that out. Good luck.
my truck had the same problem it turned out to be the drive line AFTER it messed up the tail shaft on my trans had to get a new trans ?? you can take the drive line to a shop and they will check to see if it will need to be balanced for FREE at least they did it at the shop by me