Many Thanks to you both….transmission you say? that’s interesting, and scary $,$$$.$$. The center driveshaft carrier bearing wouldn’t be the problem b/c the driveshaft was removed last spring due to knuckle bearing failure…just got the new one…Volvo part only….$,$$$,$$ … I’m almost ready to put out the 4 -500 for the front wheel bearings… by what I’m told these cars are infamous for wheel bearing problems….along with the driveshaft quirks…

I had a mysterious front-end whine that I dealt with as well.

At first I thought it was a wheel bearing, though I found I couldn't change the noise by loading one side or the other, just as you are finding.
I ended up changing the wheel bearings on both sides and it didn't affect the noise at all.

Eventually I disconnected the center (front to back) driveshaft and my noise went away. At first I suspected my bevel gear was toast. I removed my bevel gear and had it inspected (unfortunately) by a trans shop, where I discovered that there was NOTHING in there that looked like it was making a noise.

I later closely inspected the rest of my driveline and found the hanger bearing for the center prop shaft was seized - so I know think that was my culprit. I think the noise was being produced there but travelling up to the front of the car on the driveshaft making it /sound/ like it was coming from up there instead...

Here are the threads where I chronicled my troubles with this:

Front End Whine

Driveshaft Carrier Bearing Questions

FYI Bevel Gear 1998 & 1999 have unique gear ratio

Removed Bevel Gear - comments on the job

info on bevel gear rebuild

Pull your center prop shaft (not hard and not detrimental in any way) and hopefully your noise will go away. If it does I would really check out the center prop shaft hanger bearing.

keep us posted.


-Joel

"Is that ticking/clicking sound normal?"

Yes, mine ticks with the wheels off the ground & it is only front wheel drive. I would stand to reason the bevel gear would tick too being directly connected to the transmission.

A howl sounds like a bearing to me; the question is WHICH. You said you didn't hear a change from left to right during turns...take your car and get up to ~50 and then swerve HARD left & right a few times and see if the noise changes. If so, than a wheel bearing. My old car had a really loud howling noise from the front and we couldn't figure out where it was coming from; it turned out to be a bearing inside the transmission itself, which I figured out when it seized up and my reverse gear exploded backing out of my driveway one morning.

If you do suspect the bevel gear, it wouldn't hurt to change the oil in it and see if things improve.
Here's a write-up:
http://home.ripway.com/2005-4/294125/Volvo/V70XCBevelGear.pdf