Reman rack and pinion violent oscillation on jackstands

[jsm10]

I put a remanufactured NAPA steering rack on my 2007 Silverado classic. I first turned the wheel back and forth 20 times with the truck on jackstands with the engine off topping off the fluid. I then started it and did that again. If I turned the wheel too quickly the rack went into violent back and forth oscillation. It does not do this with the truck in the ground and drives fine. I did not accidentally reverse the hoses and torqued everything properly. I am thinking the remanufactured rack has a valve problem. I am now wondering if I should have it aligned or not (knowing I may end up replacing the rack again). I am also wondering about the safety of this. Any thoughts would be greatly appreciated.

[richard wysong]

it probably just had some air trapped in it. if it drives ok I wouldn't worry about it and go ahead w the alignment

[jsm10]

Thanks.  Yes, I am going to go ahead and do that.  I am the sole driver of the truck, so I can keep a watch on it to make sure there is no odd behavior that shows up.  The rack performs flawlessly other than that that issue I saw with the wheels off the ground.