Hello. Im new the the BITOG site! My '01 RX-300 still has the original fluid in the transfer case and rear differential. The owners manual call for 1qt(drain & fill), of 80/90 GL-5 in both. After putting my pinky finger in the fill hole, the original transfer case fluid has a light green color and smells like minty ...HMMMM!...I have'nt checked the rear differential yet. I have been changing out the auto trans w/ T-IV from the dealership,($3.75 a qt.)Not bad! Any advise is greatly apprciated on which GL-5 gear oil to use in these units. TIA.