I just took out a 489 323 peg leg out of my 73 Challenger. I had a 742 323 i
Had been saving for just this. You could turn yoke by hand in either direction. I installed it , put drivers side axle in first. The axle would only turn one way. I put other side in just to see if that would correct problem. No luck it only goes one way on both sides. Pulled out section yesterday, the buttons are visible were axle shafts go. Any ideas would be appreciated

have you set the bearing preload? Does the pinion turn both ways with the axles in?

maybe something "fell" into center section locking up the gears. Wouldn't take much to do that. Weird it did that.

Pinion will only turn the one way, it feels locked up going other way..with alxle in. I was assuming putting in the chunk , putting in driverside axle in first, then passenger side in and adjusting that side would be fairly easy

This is important. By design it takes much more effort to rotate the axles one direction vs the other.

Foe example, push your car forward then back, it's easier one way.

That normally has nothing to do with the rear end, in an automatic car it's due to the ORC (sprag) in the trans. With the driveshaft disconnected it should push the same in either direction unless there's a brake problem.

Rotating the axle(s) by hand is different than turning the pinion yoke which the OP states he's doing.