Tryin to swap the ujoint in my front driveshaft, which ive done a few times before.

When I try to install the second snap ring, the cap is sitting to high for the ring to drop into the groove. I've tried a socket tap, a press, smashing breakable objects around the shop, im at a loss.

Any ideas?

Have you pulled it back apart too see if a needle fell over?

Yeah Ive pulled it apart a few times, needles are straight.

It's not off by anymore than a milimeter or two. so close...yet so far.

Perchance did you happen to hit the yoke ear or ears when removing the old joint or not support the "off" side when knocking out the cap? Would lead to a minor deflection of the yoke ears. My $.02 Some quick measurements with a digital caliper would verify your deminsions

Try turning it 90 and putting it in? Is it the correct joint?

I have came across some driveshafts that had two different size U joints, when I say two different sizes I mean they are so close to the same size that they are only off by a millimeter or so and that meant the difference in getting the snap rings in, turns out I had the U joint in the wrong end of the driveshaft I switched em and it was fine, one U joint was just a cunt hair bigger the smaller would fit in either end without noticing anything was wrong but when you tried to put the bigger in the small end I could not get the last snap ring in.