I don't know how it's called, it looks like a birfield is almost the same thing internally but has a lips for the boots and are smaller then solid axle ones, so i call them birfields cause really, a birfield is a CV joint, so t's the same thing, I'm not talking about the tripod joint here. 
I'm not sure exactly what it's called either. I know that one of the reasons Toyota went to IFS was to get away from the Birfields, 'cause they are the driveline's weak spot. I think they're called half shafts or something like that.
Not trying to bust ya or anything.
Erik
