Subject: Galant Oil Filter
Question: After receiving your response to my question I called Mitsubishi with the part number from the "oil filter" I removed from the car. It seems it was not the oil filter but rather the Transmission Filter. I have done about 200 oil changes in my life and never have seen a screw off transmission filter. I purchased the new tranny filter and installed it where I had put on the "oil filter". the car was driven about 100 miles between the wrong filter and the new correct one..do you think I did any damage to the tranny with the wrong filter?I just wanted to close this out with you in case some other person makes a similar mistake.
Answer: Frank,
Wow... this is a very unique situation. Now I understand why you could have assumed that the original filter you removed was from the factory. That tranny filter probably was the original filter installed when you bought the car. It is very possible that the new filter you put on the tranny is the correct filter. I would go back to Straus and ask them to look up the part number for a tranny filter for your car. If the part number for that matches up with the new filter you installed, you should be fine. If you need a totally different filter for your tranny, remove the one that's on there now and install the correct one. Galant's have been notorious for tranny problems so don't let this tranny go bad because of a bad filter.

Reading this update and your previous question got me thinking a couple things:
(1) You never removed the old oil filter when you changed the oil.
(2) When you replaced the old tranny filter, you MUST have lost some tranny fluid. Some of those tranny filters can hold near a quart of tranny fluid.

If both the above are true, this is what I'd recommend:
You definately should do another oil change. Even though you replaced your oil, you didn't put a new filter on there. The junk that could have been flowing through your engine due to the dirty filter will diminish the life of the new engine oil. To be safe, perform another oil change; and this can also give you an excuse to use the synthetic oil and super duty oil filter like I had mentioned early ;-)

Since that car has roughly 52k miles on it, it's due for a tranny fluid change if you've never had one. If you determine from the Straus Store that filter you put on it is the correct filter, you can reuse it after you drain the tranny fluid and refill it. Here again, I would recommend using a synthetic oil. Tranny fluid should be changed every 3 year/30,000 miles. If you use synthetic, you can probably double that without problem.

Thank you very much for updating me on this. I doubt you did any damage to the car. Though you're driving while low on tranny fluid, it had only been driven about 100 miles. Plan some time in the very near future to perform both those oil changes. It'll save you a lot of headaches in the future. And don't feel bad about making that mistake. One time I forgot to install an oil filter at all! Needless to say, I made a huge mess in my friend's garage ;)
Good luck!