yeah probably the same, then again im an M35 owner not a V35 owner so im not 100% sure.
that said, i THINK the transmission change happened in the 'series 2' models. so assuming both are from the same series (either 1 or 2), they are more than likely compatible.
however, BEFORE you buy a new transmission;
check the fluid, is it at the right level?
get a workshop to flush the transmission fluid, dont be surprised if they use 9-10L of fluid.
while they flush it, get them to pull the sump off it and have a look around. might be a solenoid not engaging or something else cheap/simple.
unless the new gearbox comes with warranty, how do you know youre not buying more problems?