Scott in VA

On the track last Friday, I was shifting from 3rd to 4th. As I passed neutral, the transmission started making a rumbling noise--like the "rrrrr" sound children make with the tips of their tongues when they're imitating an engine, and I couldn't get it into any gear. I finally wrestled it into 2nd and got into the paddock, where it was towed to the mechanic. Haven't heard from them yet. Anybody else have this happen?