I have an 09 GTS. I drive it daily and I drive it hard and fast. I bought it used. The dealer has it set to change the oil every 5400 miles, however we have an Eclipse with the same motor and the oil change interval on it is the normal 3 months/3000 miles.

So I'm confused. How often should I be changing the oil?

Also, how often should I change the transmission fluid?

Should the tranny fluid be done by a certified mitsubishi motors mechanic? We only have one Mitsubishi dealer here and their customer service and business practices totally suck!

 

6000km on dyno oil 10,000km on synthetic for oil change. transmission fluid at least 48,000km before you change that. No, you don't have to go to dealership to do changes.

 

https://www.mitsubishicars.com/media..._Non_Turbo.pdf

 

Also, just noticed that only under the Severe Maintenance Schedule do you change transmission fluid every 30k miles. It doesn't say to change at all under the Regular Maintenance Schedule, just to check it.