there's 2 sections of splines with a scallop in between them which to visualize the "scallop" that it'd be like if you took a rattail file & filed a groove on a round shaft. This is what the sideways roll pin goes past so as to lock the coupler in it's fore/aft position. yes I'd drive out the roll pin & slide the coupler back up the shaft toward the firewall so you can see if everything is copacetic there. In the pic it sure looks like there are protrusions from the adjuster face that are interfering with the coupler but I'm thinking that is just camera distorsion. Holler back