Is this a coincidence?
To fix the sloppiness of my shifter, I installed the Whiteline transmission mount insert this past weekend. I also applied a piece of Dynomat on the transmission cross-member.
Miraculously, the "differential whine" that had existed since I had the 3.31 gear set installed is gone, completely gone!!! unbelievable.
The down side is that my exhaust note does not seem to be as deep as before.
2014 Mustang 3.7L cyclone engine with 6 spd transmission. Mods: 93 MPT Race Tune, 3.31 Gears, Airaid CAI, BBK Shorty Ceramic Headers, Corsa Sport axle backs, Strut Tower Brace, Steeda rear seat X-brace, BMR Rear LCAs, GT wheels, MGW race spec shifter, Passenger seat delete, spare tire delete, Moroso battery relocation to the trunk.