I had that happen on my 98 SVT I used to have. The clutch disk sheared on a particularly snappy 1-2 upshift.
I heard a nice Boom and then nothing, car just revved. It was under warranty at the time and the dealer just covered it with a new disc.

I was surprised it was just a clutch, but they wanted around $700 plus parts if the disk was worn out they said. $1600 is a rip-off. Find another dealer.

warmonger

Former owner of '99 CSVT - Silver #222/2760 356/334 wHP/TQ at 10psi on pump gas! See My Mods '05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red '06 Mazda5 Touring, 5spd,MTX, Black