My '93 Lumina has a pretty bad vibration only when turning right. I can definitely feel it coming from the left front wheel. Not really noticable at low speeds, only and higher speeds. Most noticable, say for instance, when I'm changing lanes on the highway from the left lane to the right lane. Feels like something is loose and causing the wheel to wobble.

Here's what I've done so far...
Completely rebuilt the axle shaft on that side.
Replaced the Hub Assembly
Visually checked everything and found to be okay.
Physically checked for anything loose and can find no play in anything so far.

Any ideas?