Can I mix Dex/Merc with power steering fluid (with photos)

The guy at NAPA got me a bottle of DEX/MERC and said I can use this for power steering (see photo).
The fluid in the pump is brown/green which makes me think the previous owner used ps fluid (see photo).
The damn cap says use Dextron ATF fluid (see photo).
Is it safe to put in this DEX/MERC fluid in my pump or will it ruin my steering?
I live in apartment and cant jack up my car and change fluids, bleed out system, ect.
Just a simple legit "yes, it will work" or "no, it will ruin your steering.' Thanks

 

You need to swap the fluid out. You can do it with a turkey baster and some time. get as much out as can with the baster, put some new stuff in, turn the wheels back and forth, repeat until you're relatively sure you got most of it out.

Or just live with the PS fluid and top it off. Supposedly, it comes down to what the fluids are doing to the seals. Might not be worth it to switch again unless you're also replacing the rack.

 

PS Fluid won't hurt the rack but I wouldn't go mixing hydraulic fluids if you can avoid it. Toyota uses ATF for power steering usually because it is very temperature stable in low temps so the steering won't get overly stiff and it is cheap and relatively harmless when spilled. PS fluid is a bit thicker hydraulic fluid and more expensive, usually being a mineral oil base. It can cause resistance in cold weather and provide worse wear protection for the pumps. Ever heard Ford or Honda PS systems sound like a supercharger... that's probably why. You ignore PS fluid too long and it makes the pump unhappy.

 

Yes. That Napa Dex/Merc is by Valvoline and their data sheet shows it is compatible with Dexron III. Might even say so on the back label. You can get a gallon of it at wallyword for $18. I would do as suggested and do a flush.

 

The easiest way to flush is to cap off the return port on the resivor point the return line into a bucket and turn the wheel back and forth topping off the fluid every couple turns. This method forces all the old fluid out. You know your done when the fluid runs clear.