Tony from SWestOz. the B2B is the big one on the rt side rear. Don't know what surprises the other covers hold.
SYD Racing, there is a vent at the very top, towards the front of the transmission. I am thinking some of the particles from the break of your B2B have plugged one of the internal lines and now that pressure is blowing off throught the vent. That is thre risk with a B2B replacement. Can leave a lot of jewelry inside your transmission that will take the rest of it apart in time.
Maybe it is time to look at rebuilds.