I just had my truck in at the dealership from some fluid changes. I had them change the front and rear differential fluids and the transfer case fluid.
This was the fourth scheduled "4x4 service."
They used 80W90 fluid in all three parts each of the first three times, but called me today to tell me the fluid is supposed to be synthetic.
I asked them to use 80W90 again today. I figure I made it 125,000 km with no apparent issues, but does anyone see any massive problem with the 80W90 over other fluids? Thanks.