$5.30 a qt is a pretty good price for SP III. ATF +4 will not be much cheaper. Although it might be a better fluid than SPIII. You can get Mopar ATF +4 at Walmart for about $4. You can also get Supertech ATF+4 at Wallmart for about $2.50 a qt.

As far as knowing for "Sure" if it will work? I have read a lot about this fluid and many think ATF+4 will work. I personally believe it will work too. That is just my .02.

 

Winshawn - thanks for the information and leads on cheaper fluid. Like I said, Ive been running ATF+3 for the last years with no shifting problems. I read on the mopar forums that ATF+4 is similar to ATF+3 in viscosity but has better viscosity stability. See:

http://www.allpar.com/mopar/transmissions/fluids.html

The article states that ATF+3 starts to alter viscosity at ~30k miles. I would guess that since ATF+3 appears to work in the tranny (4 quarts every 7500 miles for the last 30,000 miles), ATF +4 will probably not be a problem in this tranny. Since the walmart price on Mopar +4 is $4, I would be only saving <$20 on a complete flush, therefore Im likely just to go to the dealer.

When it comes time to flush again (2 years)Ill reconsider ATF+4 when there is more data and experience with this swap...

Intersting to note that the Mitsu maintenance schedule does not suggest tranny fluid change - ever! (or at least to the end of the schedule which is 120k miles I think) Under severe service it recommends every 30k miles. Makes me think that SPIII is infact similar to ATF+4 since it was designed to last 100k miles.

Thanks again!

TJ

 

I went to Walmar tonight and in SOCAL, Mopar ATF+4 is $4.40 qt and SuperTech is $3.02 / qt. Its interesting to note that the Mitsu Diamond SPIII fluid is made in USA and has the same bottle as the Supertech (although different color). Mitsu must be either repackaging the tranny fluid or having someone domestically formulating batches for them. i would be willing to bet that Diamond SPIII is actually ATF+4 since its a "lifetime fill" fluid as stated on the Mopar bottle. ATF+3 was never intended to be a lifetime fill - see above post. Would it make sense for Mitsu to specially design their own tranny fluid requriements when the tranny (and motor) plaforms can be found on various Daimler Chrysler products as well? I doubt it, but Im still chicken to try it.

This exercise has caused me to rethink fluid changes every 7500 miles. This currently works great on my ford F-150 cause I use Mercon III which changes viscosity rapidly. Next change, i will completely flush the F-150 and use mercon V at 20 to 30k intervals.... Mercon V is supposidely the same concept as ATF+4 - both lifetime fills....

 

do NOT use ATF+4.
you shouldnt even be using ATF+3.
Time and time again for 15 years Ive seen nothing but headaches using anything buy genuine mitsu fluid. Obviously it can be used, but I cant tell you how many hundreds of cars Ive "fixed" simply by flushing the generic or aftermarket trans fluids out and installing mitsu fluid.

 

Thanks for the advice - Im going with the Diamond SPIII.

 

Just curious, did any of those cars have ATF+3 or ATF+4 in them? I agree that Dex III is much different than SPIII. However, you cannot lump ATF+4 with all those "aftermarket transmission fluids".

 

Winshawn - tried to reply to your PM you but you have the option turned off.....

 

I gotta say, I have never had a problem using ATF+3 in any of the Mitsubishis I've owned, and neither has anyone that I know. Some of these guys had Eclipses that they ragged the hell out of, and still had no problems. I used Amsoil the last time, but wouldn't hesitate to use ATF+3 again.- Since ATF+4 is now available though, obviously I'd go with that.

 

I just flushed the tranny per the FSM and it was EASY. Make sure you have 12 quarts of tranny fluid. I think most can flush the tranny in an hour (including the removal of all the undertrays) without even jacking the car up. Its so easy that Im going to start flushing every 30k miles with my normal service.