AMSOIL SVG gear oil is not $33/quart. Get a preferred membership which is peanuts and you can get all your fluids in one place, usually at your door in a day or two. AMSOIL Severe Gear is a top notch gear oil. Ask
@Pablo for more.
I don't recommend Red Line's gear oil for daily use. It's a formulation that's extremely heavy on anti wear additives to the point where it can cause additional wear. Just look up some of the UOAs around here. It's formulated for heavy track use and abuse.
Another sensible option is Mobil Delvac 1 75W-90 in the front diff and Mobil 1 LS 75W-140 in the rear diff. Mobil makes very good gear oils.
Finally, there is
@High Performance Lubricants, one of our forum sponsors. They make very good gear oil. Their gear oil is unlike any other formulation, as in, it's modern. It doesn't rely on a heavy Sulfur-Phosphorus additive package. In fact, it barely smells of anything. I'm actually going back to it next week. Yes, I like messing with lubricants.
Transmission fluid: I recommend the company above, HPL ATF Green. Yes, it's actually died green. If you're concerned about warranty coverage and you don't want KIA to know that you changed the fluid then I recommend using Mobil 1 LV ATF HP. That's also some seriously good ATF. Skip Valvoline Max Life, it's nowhere near as good as Mobil 1, let alone HPL. One thing to keep in mind when you change to a different fluid: you should do a complete ATF replacement, otherwise you will run into weird issues down the road like akward shifting behaviour or slipping clutches. Good luck!
