Have 3800 miles on truck and I just purchased 4 quarts to change my diff. I went with the 75/140 because we tow very heavy. It was $14.99 per quart as opposed to Mobil 1 75/90 that cost half of that. Someone told me they blend half 75/90 and 75/140 ?
I have not tried that. Any suggestons ? I wouldn't think that the mpg would be much different between the two. Thanks