I am searching for a series of novels where an alien race consists of different clans.
One clan in particular can bend time and space making space travel possible. The aliens, however, have kept this clan ability a secret. Instead, this same alien species only supply a mysterious box like machine along with an engineeer in which many species including humans have taken a part to try to explain how the species stardrive work to no avail.
I remember another alien species who have a symbotic-bird creature whose job is to pick off bacteria and other materials from its skin. It has hired a human woman to discover the secret on how the previously mention alien race stardrive really works. I believe she is genetically altered.
It would have to be at least 20 years old if not older.