This gets rather involved..
There is a indexing ring on the transmision..it is a small ring with a detent in it, that a shot pin goes into, to index and hold the spindle in orientation during tool changes..
You will have to remove spindle covers to even see this ring and to gain access to it..
Then it is a matter of resetting it to the right orientation.
If you PM me I would be more than glad to give you my phone number and walk you thru it.