I just recently rolled over 120000 miles on my 07 hemi. I started to notice the transmission slipping. It probably only does it once or twice a week city driving but in the country it likes do slip going uphill occasionally. I then noticed a whine which I though was just my tires at first or even brakes. The sound starts at about 20 mph. Then it got a little worse and I realized it was something different. I jacked the truck off the ground and put it in drive and it sounds like it is definitely coming from the tranny. It's not terribly loud but I can definitely hear it over my pipes. If you guys have any idea of the problem it would be very helpful thanks.

Here's a video of it.

 

Its hard to hear. Check the rear diff. Usually a whine is a bearing going bad. looks for leaks in the rear on the back side of the rear discs. Indicates seals going

 

I checked the rear end and it has plenty of oil and it was just serviced by the shop. When I crawled up the truck when it was in drive the sound was coming from up around the tranny.