What is the difference between the 1st design and 2nd design on the front wheel hubs on the 2001? How do I know which one I need?

If I remember correctly the design different involved the internal races on the bearings. Order up some new Timken'* and you'll be fine. I would recommend that you change both and not just one. If one has gone bad, the next one will soon be there.

Yeah, but I was wondering if the 2nd and 1st design interchange. Is the 2nd design better or not? Anyone know? Thanks.

The second design for anything is usually an improvement from the 1st design, I'll go out on a limb here and say YES...the 2nd design is better, especially if it involved changing the races in the bearing.

If you're going to have one old and one new wheel hub on the car, that'* not an issue. If one is the 1st or 2nd design...that should also not be an issue. However; as I stated earlier...I woud recommend you replace then both at the same time.

Also, please add your year and trim of your vehicle to your signature line. That way when you start asking questions in other areas of the forum, we all have a better idea on how to assist you. Click on "Quick Links" above, go down to "User Control Panel" and then click on "Edit your Signature" It'* pretty straight forward from there.

So the 2nd design from the later years should go on my 2001 no problem, correct.

Yes...a second design is made to interchange and TMK they didn't change the knuckle from 00-05, you should be ok to use either w/o issues.