Steering wheel jumps along with clanking noise when wheel is turned hard.

If you are stopped and can turn the wheel back and forth, it is not the power steering.

Sounds like the transmission

Check this link for location.

Along side the battery , infront of the brake fluid holding tank
http://www.carcarekiosk.com/video/2010_Lincoln_MKZ_3.5L_V6/transmission_fluid/check_fluid_level

I hope you are using the right PS fluid for your vehicle! Have you checked that?

Power steering systems are tricky. Whenever you add fluid, you should (with the engine running and PS pump turning), turn the wheels ALL the way, both left and right while creeping as slow as a snail on an open parking lot ... at least twice (like R-I-G-H-T, then L-E-F-T, then R-I-G-H-T, then L-E-F-T)! Then re-check the PS fluid level again, and if still low, repeat the whole process! DON'T turn the steering wheel too fast!

You likely have a bad power steering pump or a hose that is leaking. Do not put any fluid other than power steering fluid in the power steering reservoir. if you do you will wreck the hoses and pump. Better not drive it till you get it repaired or you may ruin something else or have an accident.

I would go back to the oil change place. Fluid levels are their responsibility and you should have a trail of fluid from the leak. If you had no problems before the oil change and immediately after you have problems, then they are the people to talk to.

There are some basic systems that are to be checked when doing an oil change. Power steering fluid, washer fluid, and auto trans fluid are normal items the shops keep on hand to put in cars.

Now cars with rear differentials and standard transmissions are checked on request. Your problem is something that should normally be checked by a shop doing an oil change.

Some of the better shops grease the fittings, check the belts, spray the battery connections and check the Antifreeze.

If the Power steering was out of fluid, the pump may be damaged. There are also different fluids to use for each car company.

Please rate my info.

more than likely it is just low on power steering fluid. system might have air in it now. so after fill power steering unit to proper level driver the car and check fluid level again. and add more if needed . I believe car should have motor running for when checking fluid, same as transmission.

I'm going to agree with the rack conclusion. Keep in mind I can't see it for myself.
If you take the load off the front wheels, you should be able to turn the steering wheel without effort.
If the effort changes while turning the wheel, the only things affected would be the rack and the column.
If you notice it turns ok with the engine off but not with the engine running, it could be something with the pump or one of the lines, or still something with the rack.

could be the c/v axle, the ball jount. or the powerstreering belt is loose

This is a suggestion, but may not be the answer. Further information will be required to accurately diagnose your situation, which may be two separate problems.

The whining noise you hear while driving and turning can be attributed to 2 different things:

1. Power steering pump/apparatus. If you've run the pump low on fluid, its bearings may be wrecked. This will cause additional strain on the engine, lowering your fuel economy. You can note this situation by the feel of the steering. Is it hard to steer while sitting still or at parking lot speeds?

2. Transmission internal gear sets/clutches. If the whining noise occurs only when in forward or reverse gears, and not in park, it is probably something along the input shaft of the transmission, which could include clutch packs, torque converter, and bearings. If the noise goes away when in Park, and steering the wheel while sitting still doesn't make it come back, disregard option #1.

Based on the situation, I'm going to choose to elaborate on #2, as I presume this is your problem.

Since you note that the problem is there when you drive and when you turn, I'm recommending transmission service. At the very least, check your fluid level.

When is the last time your transmission was checked/serviced? More than likely, you've either lost some fluid and it's running low (which can/should cause other problems as well), or the fluid isn't getting where it's supposed to be getting. Either situation will cause severely increased fuel use.

CV shaft replacement needed cliff

Is the belt on the power steering pump tight or loose does the pump makes a huming noise when turning steering all these are causes of hard to turn steering belt need to be (tight) on pump and pump must not be huming when turning steering add fluid if needed and play with steering to see if help if not need to replace pump