questions about my 99 model?

Hey everyone, been tinkering underneath my new truck (99 z71 new style) anyway, got some questions...
1) what's up with the steering? it looks like a half and half rack and
pinion system/recirculating ball? is it any good? had grease fittings on the pinion arms(?), so i greased 'em just to make sure..any problems with this set up?
2) got a 'tapping' feeling in the steering wheel when i turn it in normal driving..was told it is an 'intermediate steering shaft' or that common?(truck has 137K miles, i guess common went out the window 40K miles ago) could it be something else?
thanks in advance

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