I get this odd reverberation that cycles around 60Hz and only occurs in fourth gear and around 95km, can hear it and feel it, not necessarily through the steering wheel but everywhere. Any faster or slower, the reverberation is gone. Doesn't occur if I'm in third or in a higher gear. At any other speed or gear, I don't have this.

Not sure if it's tires or not, or the combination of the tire noise, engine noise, wind noise (all windows are up and sunroof closed) that's causing the reverberation but I'm at a lost to figure out what's causing the sound. I'm going to probably put on the winters on soon and maybe the sound will go away but thought I post here to see if anybody has an idea what might be causing this.

if it only happens in fourth at a particular speed, it has to be coming from the gear box and vibrating through the car...

Bring it in and take a tech for a ride. Could be a defective part within your tranny. They may come up with some line of crap to tell you too! If you don't get taken care of by your dealer/service center, call Audi Customer Service @ 1-800-822-2834. They're usually very helpful in getting situations resolved.

Good Luck!

The tech advisor was in today so took him out for a ride. He never seen this issue before but suspects that it might be related to the back pressure contributing to this. Now I did have the stock exhaust removed then put back on so it's probable that there is a slight leak under. Oddly though, the reverberation occurs around that speed whether I'm on the throttle accelerating through the 92-97km range, keeping the speed consistent or off the throttle coasting.

Anyways, don't think it's anything serious, just curious.

The Subaru I traded in did that. It was a 5mph range (75mph to 80mph) it'd vibrate. Before and after that it was ok.

Turns out the tires would lose a little pressure causing some kind of inballance. Check the tire pressures and make sure they are the same at least side to side

I was between 30 and 34 psi and now they're all about 35 psi. Sound still there. Will have to see if it's still around when I throw on the Kumo winter tires sometime over the next few days.