The spline movement is directly related to the load on the springs- - - - -more weight, more spring flex, longer stroke on the splines. A quick way to monitor spline movement is to snug a zip tie around the spline, and push it up against the yoke. As the spline moves in and out the zip tie will get pushed back to the maximum point of travel and stay there. It's the same way we would monitor suspension travel on the race car by putting a zip tie on a shock absorber shaft. Three big guys jumping up and down on the front bumper couldn't move the suspension as far as a couple of hot laps around the dirt track would!
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!