ggg.....,
I'm going to assume you have what I call direct linkage for the steering. In other words no isolator from the rack right up to the wheel.
Flaming River Industries has a very, very good one that you can put in the lower section of your shafts. This should eat up about 75% of the bumps and jerks, it could take 100% of the vibration away. Last I looked....$125.00 ??
DV