Do you really need the collar? You're going to shorten the splined end of the shaft, why shorten per the instructions? The PTO coupler is splined thru, so why not machine the that end so it has 1/8 - 3/16 off the end of the crank? If you chunk it up in a lathe so the face is square to the splines then there is no need for the collar. The collar is there so the shaft doesn't move too far forward and comes out of the trans. If you set the end-play to the crank, the collar is useless.