For the past 100k miles, my 84 240 wagon (Automatic) has been generating a soft whine from the differential. The noise occurs only between 60 and 65, disappears at 70 or 55 or if I release the throttle. Car has 250k now and is in such good shape (quiet) the predominant noise I hear at 65 is this noise. I tried using synthetic 85w140 on the differential, tried various additives, even changed all the rear end bushings, the noise is still there. My local Volvo specialist said that this is a chronic problem on all 240's and particularly loudest with the wagon due to its body design. He also said that a rebuild with new crown/pinion/bearings ($1500!!) may not solve the problem because from his experience having done this a few times before didnt produce guaranteed results. He could be correct about the body design, the noise is lessened when I carry passengers and/or cargo. I would like to hear opinions about this problem before I go ahead and rebuild the thing for $1500. This is such a good car I think its worth the money. Thanks,

Alex
240 Wagon in Los Angeles