Wow, I am an idiot. First time with manual here, guess i could of just googled that question. Sorry for my abruptness, I was in a get stuff done mode.
I called all napas in my area and the only thing that's 75w90 gl-4 is synthetic. I would like the 75 cause it gets cold once in a while, and I'm a fan of less resistance if possible.
Anyways, I am so confused on synthetics, is it cool to switch to a full synthetic gl-4?