Loud repetitive noise coming from front tire in 2 wheel drive, goes away when in 4 wheel drive.

Had my tires rotated before a long trip (~120 miles). The mechanic noted "both right side ball joints loose".
No problem on my way there, but coming back a noise started coming from the front tires. When I switched to 4 wheel drive, the noise went away. I drove about 50 miles in 4 wheel drive on dry pavement at ~40 mph and noticed a smell like burning rubber or something similar. When I looked in the driver side tire area, there was some kind of liquid film that seemed to be leaking/spraying. I switched back to 2 wheel drive and put up with the noise for the rest of the trip.

– Loud repetitive noise coming from front tire in 2 wheel drive, goes away when in 4 wheel drive.