Gearbox code

Hi I have a 1999 Octavia LXI and I need a new gearbox, I can't find the gearbox code to order one, does anyone know where I can get the code from, I have looked in the boot but the sticker is badly warn and cannot be read, I have looked under the bonnet but nothing and I have looked in the service manual where I found the code DYVS, I have been told that it should be a 3 letter code, so please help,

Thanks