the uni-joint would have been very noticable when you removed & replaced the rack, so i don't think you could've missed it.
the ball joint on the bottom, and the bearing in the upper mount are all there is, besides what you've worked on.
i think you've got the rack to pinion gear adjustment too tight.
there is a "pad" that holds the rack against the pinion.
on an old rack with some wear, that has to be adjusted so that the relatively UN-WORN places on either side of center to the end will move freely, and not adjusted for only the center position.
thanks man, will investigate this on the weekend, thanks for ur help.