I bought some of that purple synthetic stuff for 15 per quart; got 8 quarts. I disconnected the return line, pulled the plug and drained, replaced the plug after cleaning the metal from the magnet.

I turned on the vehicle until the return line stopped spurting, then I refilled with 2.5 quarts, and then I drained the 2.5 quarts through the return line with the transmission in neutral. As soon as the line stopped spurting I turned off the engine. While the new fluid was in I reconnected the return line and shifted through the gears. My haynes manual reccomended replacing 1/3 of what came out (4 quarts, maybe 5), and flushing in increments.

I did this once more, filling 2.5 quarts, shifting through gears, purging 2ish quarts.

My car is an automatic. It is a 2003 galant. It calls for Diamond ATF SP III or equivalent. The purple stuff expressly states that it is compatible with Mitsu Diamond ATF SP III cars.

My car is slightly noisier than before. It had 145,000 miles on it and I doubt the fluid was ever changed. I am hoping I did not harm it by running it on a low amount of tranny fluid. But I only let it run for less than a minute with each 2.5 quart replacement, not counting the fluid that remains in the system.

I am hoping the slight difference of sound will clean up and I wish to know if I did something horribly wrong. What do you think?

Also my car has an external filter for the tranny, according to advance, autozone and such. Yet I cannot find it for the life of me. The Haynes manual says so too, but I call horsepoop because it should be large and by the dipstick and its not there. I looked under the car for two hours. Wish there was a picture of its placement so I could rule out my own ignorance...

 

bumpity

 

I am no expert on Mitsubishi or transmissions but did you fill up the transmission with fluid fully? You mention that you flushed it out and such but did you fill the transmission up with enough fluid?

The way I read your post, It sounds like you didn't but I am not 100% sure. Sorry, I don't know where the filter is but sometimes it does stare you in the face without you knowing it. Just a thought.

 

I did not fill it up fully. I dropped close to 4 quarts (holds 8 i think) until it wouldn't drop any more. Then I shut off the car, reconnected the return line, added 2 quarts, and went through the different gears. Then I dropped 2 more, added 2 more, went through gears. Then I dropped 2 more, added 4 more for a complete fill. Having read more about it this is not the orthodox way to do it, but each of those times I ran with 2 quarts shy was for less than a minute tops.

So counting the final fill which is incremental, probably about 5 min total on 2 quarts shy. The tranny does feel different. Fluid is clear. Its hard to describe but the car feels "heavier" yet more responsive. Almost like its not down shifting quickly enough... it is though... thats just how to describe the difference in how it feels. Makes the car feel slightly stiffer, but also a little more responsive. There is some overlap here too because I am seafoaming the crankcase, I have seafoam in the tank (half can), and I have seafoamed the engine 3 times (2 times with a third of a can and once with just over 3/4) using small "sips" to avoid hydrolock. Hard to tell what is making what difference.

Called the dealer in another city since there are no mitsu dealers within an hour driving range here. Says the filter is either obvious or not equipped. I looked for 2 hours, wow. Apparently they can't tell me based on my VIN which makes no sense. I have a mystery car, according to two dealers. I'm gonna do an inline magnafine filter to soothe my tranny paranoia.

 

I did a quick search about your car and its filter for the transmission. It can have 2 kinds of filter on it. One can be the external type which looks like an oil filter or it could be an internal filter which is just a screen inside and is usually cleaned when you have your transmission rebuild.

Or what is know as a "Back Flush", Ask a transmission shop these things. They probably might know more. This is the link I found when looking it up. So technically, I would say you cleaned it out already but may want to speak to a good shop about it anyways.

Cannot locate transmission filter or instructions to replace - FixYa

That's the link so you can read it yourself if you like. As for the behavior of the transmission, It is probably from the heavier oil in it. What I mean by that is since it is new oil, It has all the additives and what not in it giving it a bit more weight to it compared to your old oil.

Drive it around some and let the oil travel some. And make sure it is full.