99 sierra 1500 z71 130,000 miles. when stopped i can only turn wheel 1/4 turn in either direction before it will feel like no power assist. while driving it is fine does not feel funny. gear box is leaking very little. curious it it would be a problem with pump or steering gear. anyone got any ideas?

 

You'll want to check the Pitman and Idler arms for play. Lift 1 wheel off the ground and try to turn it back and forth. You'll see the Pitman & Idler Arms going up and down (if they are bad). These trucks are famous for having issues with the 2 arms wearing out (not the arms but the joint at the end of the arm). After 130K miles it is due. I recently replaced mine a bought a Cognito Motorsports Pitman & Idler Arm support. It makes a huge difference off road and when I lifted my truck and put 35's on it.

Check out the supports here. They are worth every penny!

http://cognitomotorsports.com/store/pisk6.html

 

Pitman and Idler arms won't cause the loss of power steering. From what you described it sounds to me like you may have an internal problem in the gear or the power steering pump. One test you can do is while in park, engine running, rev the engine to around 2000-2500rpm to speed up the power steering pump and see if the power assist kicks in more. If it doesn't you probably need a pump. If you see no change with the increased pump speed you may need a steering gear given that there is nothing else binding up in the steering linkage.