If there were burrs and paint it can take some force. Perhaps the gage is not reeding correctly, because it still sounds like a lot to me. If you were to drop a needle and then force things to go together enough to get the clips in you should see a dent or crack in the end of a cup from the needle trying to get out. I assume you would notice that, and you did not say anything about it, so the u-joints must be fine.

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-