My 2003 X-type (auto) has started to "whine at 25-30 mph. 100,000 miles on the car. It sounds almost like a higher pitched wolf cry. If you go slower it goes away, faster it goes away. I took it out of gear, no difference. I turned on the A/C, no difference. It seems to be coming from the passenger side axle. Wondering if it's an inner axle bearing? It's been cold the last couple days. This is a weird one...

 

Sounds like the centre prop shaft bearing. Not an easy thing to replace but you could try the method of injecting grease into it that has worked for some others. I've also read that it can be because of harmonics in the drivetrain which can be fixed by changing the rear differential oil. If you use the search function you should find the thread about greasing it, worthwhile to at least try before moving further.

 

Prop shaft centre bearing is normally a good candidate, but most comments about noises from that tend to become evident often at higher speeds 50+MPH.
Half shaft CV joints not likely to make that noise but the wheel bearing could also be a viable candidate.

Dare I mention the transfer case......they can get pretty noisy due to lack of fluid maintenance.

Don't know how practical it is for you to get the car safely up off the ground and emulate speed to allow you the chance to better pinpoint sound.

 

This gentleman has the same problem.

 

I'd still be inclined to say that it is indeed the centre bearing, more so if it is intermittent at all. Wheel bearings can be tricky to diagnose with ears alone (notably which one) but a decent mechanic should be able to feel for one with play or excessive drag. The transfer box is an expensive fix if it is the culprit but I don't know how that would be diagnosed accurately.

 

I believe I will change the transfer case oil first and then if that does not work I will change the carrier bearing.

 

Drained and changed the oil in the transfer case.




The whine was still present at first but went away. The temperature is warmer and it only exhibits itself it cold weather. I'll find out when the temperature drops in a couple days.
Needed to be done and the car seems to drive smoother. I would recommend doing this around 65,000- 70,000 miles or so. I used Amsoil severe gear oil.