70 Challenger: steering wheel has a mild vibration only at idle in D at a stop. Driving, all is smooth no matter the speed.
If I have my hand on the wheel at a stop, I can feel the vibration. If I let go of the wheel at idle in D, the wheel vibrates.
What should I look for?
No knocks, no noises.
Engine mounts, loose steering unit? Do I need a rubber insulator on the steering column?

Thanks!