Especially change it if you tow. The manual says to change with your first oil change when towing. I did, and it was dark! Haven't changed since (we're at 11K), but plan to at 15K, probably to synthetic.TooTall said:Was searching around on the Titan site and saw that many are appearing to have differential fluid problems. Looks as if they are overheating and what not. Has anyone replaced their fluids yet? Which weight oils?