If it's that tight on the spline, you'll never get the yoke through it without totally destroying it. Try comparing sizes with the original seal, and I'll bet you find the old one has a larger inside diameter. The lip should be a snug, but not excessively tight fit on the hub of the yoke, not the input shaft spline.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!