1994 Cadillac Deville Thumping Sound & Catch In Steerin

I have a 1994 Cadillac Deville; awesome car. One problem - when I turn it to the left, it makes a slight thump sound and I feel like a catch for a brief moment. After getting past that point (which I haven't had a problem doing, so far), it steers and sounds normally.

When turning back to the right, it's non-existent. It only does it once you start turning to the left. For example: after turning right, once you begin to turn the wheel back to the left, it happens. Doesn't matter if you're recovering from a turn or simply keeping it in the road. It only happens when you begin to turn to the left.

Please help, I don't trust driving it in this condition - at least until I understand more about the issue. Thanks!