Default Rear yoke bolts chewed up

Pulling my old rear out to install a 9" (86 short bed C10)-I found all 4 bolts that hold the
U joint to the yoke smashed, had to use a vise grips to rem them. The pinion angle wasn't
perfect, some unknown rear, but wasn't super bad. I can find nothing with a witness mark
that shows what the bolts were rubbing on, just strange. I would have to think it would take
an extreme drive line angle for the bolts to be anyway near touching something, then it would
leave a mark. Anyone ever experience something like that.
The rear was lowered 4", and I rem. a leaf, and it was an open rear. I cant imagine the rear
was trying to climb up (no traction bars yet) but then i would see a mark on the driveshaft.
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