Gearbox gone pop

[manca]

2005 face lift 3.0tdi.
Went into safe mode on the way to work this morning after having a fit going between third and fourth gears.
On the way home same thing.... started off okay but half way home (a couple of miles) went back into safe mode and third gear. I slowed down towards a set of lights which turned green as I approached. Touched the accelerator something went pop and I lost all drive. No gears at all..... stuck in the middle of the road awaiting rescue