removing rear spline from tailshaft

I am making a guess, but it is probably an air-lock (vacuum) caused by grease in the spline. Try removing the grease nipple to let some air into the joint.

Have you unscrewed the retaining collar....It functions as a scraper along the splines and to retain the two pieces together!

Matt.

Just another point to remember.
Make sure that you mark all the bits so that you can reassemble them in the same alignment. Failure to do this can result in all sorts of problems. (vibration and excessive Ujoint wear in particular). Otherwise it's a straight forward job.

Disco