I am getting ready to change the differential and transfer case fluid in my AWD Sienna. Service manual calls for GL-5 75W-85, so I am sure that the Mobil-1 75W90 GL-5 gear oil will be just dandy. Here is my question, though. I have a spare quart of Mobil-1 75W140 left over from my truck days. My guess is that it would be too heavy for my Sienna gear train, even if mixed 50/50 with 75W90. Thought I would ask the experts though. Thanks.