I am trying to figure out if my 1990 Toyota 4x4 22r manual transmission (my baby) has any yellow metals in the transmission or transfer case?? While researching I keep seeing everyone pretty much recommend a GL-5 80/90 in the diffs. For the manual transmission and t case I keep seeing GL-4 or GL-5. Back when I had my 00 Volkswagen GTI I couldn't use a gl-5 due to it having yellow metals in the manual transmission. So I want to make sure this is not the case on my truck. While researching I have found one person mention yellow metals in the transmission of my truck. Not sure if this is true?? Everyone else is saying GL-4 or GL-5 80-90 I figured this is the place for the correct answer and hope you all can help.