The pass. cv joint blew out in my 97 Legacy. So I go to the local parts store and buy the whole axle. I pulled the steering knuckle off (a story in of itself!) and popped the pin out of the inner cv joint where it attaches to the stubshaft and gently pulled it out of the gearbox, BUT the stubshaft came with it. My cheapo manual doesn't mention a word about this, plus on the splined end that goes into the gearbox there is a "C" clip in a grove about 3/8 of an inch from the end of the spline, hence the spline only engages about 3/8". I work in maintenance in a power plant and although I am an Electrician I have helped the mechs on many a job. My gut feeling was "this isn't right" I hope I am wrong but figured I'd ask someone in the know.
Thanks
Mike in NH

 

That is the lock ring, you have to stab it in with a some force.