ford transit radio 4000rds code required?

i have recently changed my van battery and have lost my radio code. can anyone help me with this code please as i really don't know from where to get it ?

serial number of radio 4000 rds is: m477743

thanks a lot for anyone who could help me

Vernon RG, March 2014

It worked!!!!
Thanks Raz

VernonRG, March 2014

It should be 7763.

Raz, March 2014