tomcruise12354

I recently put in a new transmission (m6) in my 1999 formula back in December, and ever since then I got this bad vibration in the drivers side seat around 50mph-up. It seems to get really bad around 70 to 80mph.

So what I did was jack the rear wheels up to see if the tires are what's causing this and apparently they weren't this sound is.

I put my phone under the driver side near the jack point for the car just to capture the sound.

The engine doesn't seem to vibrate in neutral

I dunno what this is?