automatic transmission fluid?

Your Santa Fe uses Hyundai 00232-19057 SP4-M transmission fluid if it is the conventional automatic. Looking at the compatibility on their bottle it only lists the SP-3 so I wouldn't use it.

Where do I buy the 00232-19057 SP4-M transmission fluid from and how much it cost?

You can get the OEM fluid from a dealer or look around for fluid that says it is SP-IV M compatible. There are a couple companies that have it, many parts stores can also get it if they don't have an equivalent in stock.

https://www.hyundaipartsdeal.com/genuine/hyundai-atf-sp-iv-m~00232-19057.html

how do I know if the fluid is bad? The fluid I drain out the color of it is a dark color.

Hi,

Transmission fluid should be a translucent red color. If it is dark, chances are it is dirty or burnt. If that is the case, I would recommend servicing it.

Take a look through this link and let me know if it helps:

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

Take care,

Joe