tranny noise

I know someone who has a 91 mk3 turbo, verry modded. anywhoo it took it to alocal garage and had anew ecu and harnes put in, and he had some simple tranny work done, clutch bleed and fluid in tranny. so he drove north about 2 hours both way with out tranny fluid, the tranny crapped out then he pput fluid in it it has been driving ever since. what could have happend? oh yea, it only makes this noise when clutch is out and fifth gear has to be held ion and double clutch into 3rd