Fuel Saving Tips
If you have a rear-wheel drive car and you haven't changed your differential fluid in 80-90,000 miles, it may be good to replace it with something like Redline 75w-90 or other synthetic gear oil. Also, if you have a manual transmission you should replace its oil in that same time frame with something like Redline MTL or other synthetic oil. I have done this on my last 3 vehicles and on average saw a MPG increase of 1-3 MPG and I experienced smoother shifting.
posted by kd7iwp on February 22, 2012
this tip works for 92% of voting Fuelly members.