In the 03 4-banger, auto, when I hit 55-65 and it shifts into 4th the car shudders and hesitates for a moment then smooths out. car has 115,000 on it. I know the car needs a tune-up, fuel filter, air filter. Do these trans have filters like American automatics, how difficult would it be to change? I don't know anything about these transmissions. And on a side note, what kind of muffler would you suggest for this car, going for loud.

 

that is a 40/50 series trans. the filter is inside of the trans and is not serviceable unless you take the rear case off. not recomended unless you rebuild. fuel filter is located inside the fuel pump module that is in the tank. have to remove pump and dissassemble to replace. could be your trans fluid is badly deteriorated, or the wrong fluid type. have to use mitsubishi fluid. sp3. fluid from autozone ect.. can make the trans shutter. bad coild boots or plug wires can also cause a shudder on heavy acceleration. spark plug tube seals can leak and let oil get into the plug tube and shrt out the plug casing a shudder. these are the common issues on that model

 

Thanks man. Changed the air filter, it was black. Actually made a difference with the engine. Gonna find a good tranny shop and get the trans flushed. Then I'll give her a good ol' tune up. I'll change the fuel filter if and when the fuel pump goes out. Again I appreciate the input. I'm new to the mitsubishi world.

 

Sounds like a torque converter shudder, try flushing the trans fluid.