All,

My new to me 2009 LR3 with 108,000 miles is making a loud whine at highway speeds. Starts around 65 mph and is only noticeable when lightly accelerating, but goes away when off the throttle or accelerating heavily. The noise gets worse at 75+ where it is noticeable regardless of throttle input. The diffs and transfer case have fresh fluid in them. The previous owner has replaced the front diff with a reman unit and both front wheel bearings within the last few years so while I’m not ruling that out I’m wondering if it is a transmission or transfer case issue. The noise does not seem to vary when cornering so I’m not thinking it’s be bearings. Any input on the cause would be greatly appreciated. Link to a video with the noise is below:

 

I have a similar-sounding '05 LR3. Wheel bearings are good. Diffs seem good as does the the transfer case. The driveshaft, however, needed attention. The carrier bearing AKA Center Bearing rubber was shot. I planned on replacing it with a new one, but once I got the driveshaft off, both the CVs (front and middle) were not tight anymore. I noticed some play. The rear U-joint was notchy and not very smooth. So, time to replace the entire shaft.

I'd do a quick inspection of your driveshaft. If it moves side to side a bunch, then remove the heat shield to check out the center bearing especially the rubber isolator. If that looks bad, remove the whole shaft and further inspect. Removing the drive shaft is pretty easy. Took me about 30 minutes to pull it off.

I noticed on deceleration I'd get a fair amount of noise from the shaft. Mine wasn't a high-pitched noise, but otherwise similar to yours.

Hope this helps.