Diff build w Yukon dura grip....cant get C clip back in

[Leverhead]

Hello all. Have an interesting issue with my 64 fleetside 1/2 ton. Rear is a '65 30 spline open 3 :73 and needed a rebuild so went with Yukon LSD dura grip and new motive gears (3:73 again). Got it all set up and cant get the c clip back in the driver side axle....spring plate is in the way. No issues with axle seal or bearing...just seems to have run out of splines and cant get the axle in any further.

Used the same carrier in my 75 blazer w no issues....longer axles but same 12 bolt housing. Yukon lists this carrier for all 12 bolts 65 and up.

Pic attached...going to make some calls. Will post findings.

Any have this issue before with a posi unit and how did you overcome?