I agree, but only because you list in New Mexico. The service manual says to run ATF in there but back in my younger dumber days, I couldn't wrap my head around this? So I stuck 90 wt gear oil in there and forgot about it. The next cold morning my shifter was like stirring mud for the first 30 miles. I went back to ATF and called it lesson learned. Since then, I've heard of running everything including 10w-30 in there. I agree, stay away from hypoid gear oils or anything with friction modifiers.
