My santa fe will need an atf change before winter hits. I noticed castrol was on sale. I believe valvoline is in there from the last time the owner before me changed it.
Check the product labelling and Product Specification Document for vehicle application coverage.
I think what most people mean is that not all ATF fluids cover all vehicles, and that is true.
For example, you would not want to use a Chrysler spec ATF+4 in a Kia. However, they will all MIX chemically, but that does not mean that ATF+4 should be used in a Kia's tranny.
Originally Posted By: zerosoma
My santa fe will need an atf change before winter hits. I noticed castrol was on sale. I believe valvoline is in there from the last time the owner before me changed it.
will they mix?
Having owned a 2008 Santa Fe and been involved over at HyundaiForums for some time, I can tell you both Castol Multi-Import and Valvoline Maxlife ATF both work perfectly in the Hyundai F4A51 trans that you have. I've never read where mixing them is an issue. Any ATF recommended for use where Hyundai/Kia SPIII is specd can be mixed.
Any time you do an initial drain/fill, you're mixing ATFs. It's not a problem provided it's spec'd for your vehicle.