Just use Diamond ATF SPIII

Just changed trans fluid. Went cheaper route and used the Castrol import synthetic. The trans didn't like it. Caused very bad shudder. The Castrol did state that is an equivalent to the Diamond SPIII (ass holes). Had to add Lubegard Platinum ATF Protectant. Still had shudder but somewhat improved. Then added Lubegard - Dr. Trannys Instant Shudder Fixx. Much better then, almost gone, however still episodes. Will need to completely replace the new trans fluid with the Mitsu fluid. Due to my cheapness, caused by unemployment, it is costing me double what it would have if I had just used the Mitsu fluid to begin with. I hate proprietary things but I hope there is a good performance reason for this.
Just some advise.

2003 GTZ with 106,000 and still a bad ass!

Yeah man mitsu trannys dont like non-oem fluid, been like that for a long time. The Diamond ATF SPIII can get a bit expensive, but it the right stuff for the job and will prevent the trans from giving you trouble.

where could i get the oem liquid and how many quarts do i need . i was replacing my radiator and lost fluid . so i went to walmart and bought 8 quarts of valvoline maxlife dex/merc atf so now i dont know what to do . i dont know if i should just add this fluid to the existing or not im confused . how much would it cost me to get real mits atf .

Real Diamond SPIII can be bought from any Mitsubishi Dealer. The part number is ACH1ZC1X05 and costs $6.35 per quart. For a drain and refill it took six quarts or so. You can find a case (12 quarts) on ebay for $70 -

http://cgi.ebay.com/ebaymotors/Mitsu...Q5fAccessories

You can get 12 quarts shipped from Cherry Hill Mitsubishi for $75. Currently their price is $5.58 per qt. I don't know if you Galant guys have any discount codes but if you use "3si" you can save a couple of cents lol. I just got my galant and will be doing a whole lot of preventative maintenance.

www.mitsparts.com