I remember the issue Steve mentions, though never had one like this myself. Unless this is an old case it shouldn't be a problem anymore.
I think the 4 gear tranny's have been moulded now, but the motor plates have not been cut yet. Chazz also wants the new rear bulkheads (and rear carbon towers) to be available at the same time. I think the bulkheads have been shot but our carbon supplier is based where the forest fires in California were
I can't wait to get the new finalised new tranny in, it's proper good!
Chris gives good advice above. One other question, what colour idler gear are you using, an off white or grey?