Reposting this in hopes of solution-

Hi All,

I have a 2011 Honda Accord with 130,000 miles.

About 3 weeks ago I noticed a strange whirring noise while driving at a reasonably low speed - less than 25 miles an hour. It's fairly inconsistent and only happens occasionally. More recently, I noticed this whirring, accompanied by what sounds like engine revving, is happening after i drive down a hill or apply the breaks to slow down on the highway when encountering traffic. Even after the breaks are done being applied and while driving on a regular flat road surface, the whirring and revving persists for a bit until eventually the car appears to shift and the sound goes away. I also feel as if the RPMs are jumping to 2500-3000 when pressing the gas pedal lightly following going down the hills - this only happens after this type of situation. 

I am very nervous about my transmission beginning to fail. I brought my car to a very reputable local mechanic and they drove it with me and told me it shifts smoothly and that I am worried about nothing. Since I did this the issues have only persisted. Hoping to find some answers here. I appreciate the help very much.

VIDEO OF THE WHIRRING
https://drive.google.com/file/d/18VDiTlbp8GHQfYmgDy4B6sh2uziLkjx_/view?usp=sharing