New user with the shakes!

Hi guys, I'm new to this but have a 110 CSW. The last few days when decelerating and getting to approx 40mph there has been a shake from underneath that goes thru the gearstick and shakes the whole car. We recently changed the uj on the front of the front prop. I've just noticed that the sliding spline joint is at the rear not the front as per Haynes manual. Would this cause the problem?

:welcome2: and dunno