New Owner, New Member, and a CV Boot Question (Pics!)

[Dupersenior]

Hey all, I'm the proud new owner of a 2004 X5 4.4i. It's my first BMW (and the first car I've ever bought). I flew out to Chicago last Saturday, bought it, and drove it all the way back home to Northern VA by Sunday. It's Sterling Gray, with Sport Package, Premium Package, Cold Weather, 19s, Nav, and basically all the doodads except PDC (bummer). It's even got the slide-out load floor, which is a really neat feature that I'll probably never use. About 104k miles on the clock, but it's in spectacular shape inside and out. I absolutely love the way it looks, sounds, and drives. It'll be more adventure-mobile than daily driver, so hopefully I'll be able to keep it going for a very long time.

Xoutpost has already been a great source of information - I got a very fair price on an OEM tow hitch from BMW of Bloomfield, based on the recs from here.

Here are some pics taken by the dealer:




I love the black interior w/ light poplar trim:




Anyways, that brings me to my question. During the drive home from Chicago, I could hear a very quiet 'wum-wum-wum' noise coming from the left side of the car. The noise increases with speed, and it seemed to be one 'wum' per wheel revolution. I figured it was probably a wheel bearing on the left side just starting to go bad, because I've had that problem in other cars and it started out sounding similar. It's barely audible - you can't hear it sitting in the passenger seat. No vibration or tracking issues either.

Earlier today, I was talking to a friend who also has an E53, and he mentioned the CV boot issue they have. I went out and checked, and sure enough, both sides front outer CV boots were torn. They aren't gaping wide open, but they're definitely split, and some grease has leaked out.

So my question is, could the CV joints possibly be causing the noise I'm hearing? The noise doesn't seem to change with turning, braking, or accelerating - it just depends on speed. I've also heard the CV joint noise described as 'clicking', and this is definitely not clicking. It sounds exactly like road noise, only pulsing (like I said, 'wum-wum-wum').

It's important for me to figure out which one it is, because if it couldn't be the CV joints, then the joints are probably fine, and I'll just replace the wheel bearings and CV boots. If it is the joint, well, then I'll need to buy a whole new joint assembly (or maybe two).

Also, if it could possibly be either one, is there any way to check which is causing the noise before I start doing major dissection?

Thanks in advance for the help.