I wish I could remember how I determined what was the hum but I sold it 2 years ago. However, after I did the tie rod end replacement, I did a check on the lower ball joints and found each side to have excessive play. I replaced both lower ball joints and while there also replaced both upper ball joints and the tie rod end on the passenger side. Now that I think about it, that helped to make it go down the road quieter when I did a road test in neutral and let it coast. After that replacement work, I took it and had the front end aligned and that, combined with the parts replacement, really helped quiet the front.