When you change your transmission fluid, always use the recommended fluid. (1989-91 owners, ignore the manual and use ATF+4).

Don't assume your mechanic or dealer knows what fluid to use. Ask them to make sure. (Some people recommend watching the mechanic pour it in. We have been told about mechanics who said they were using ATF+4 when they were not.)

All Chrysler (and Honda and Toyota) four-speed and six-speed automatic transmissions* are very sensitive to the quality of the transmission fluid. Only use ATF+4 in these transmissions. Do not use Dexron or Mercon.

Some companies sell "universal" fluids; if they state that they are compatible with ATF+4®, they should work, and can be helpful for those unsure of which fluid to use. The Center for Quality Assurance warned us to check the label for Chrysler’s license number, and to make sure the fluid is on their list of ATF+4® licensed and tested fluids.

 

That's what I run in my bigblock 727 with a manual reverse valve body. ATF 4. Come to think of it I also run that in my truck's A518 tranny.

 

I was going to run Dextron III again but came across this post at Allpar.com this post is important im glad someone on the forum can attest to this.

 

Most of the late 80's early 90's called for ATF+3 which is NLA, sperceeded by
ATF +4 Older TF can still use Dex III

 

Go by what it says on the dipstick. The manufacturer knew what friction materials were used in the clutches when it was made. Chrysler went to a more highly friction-modified fluid (the + fluid specs or 7176 D/E) when they switched to more advanced friction material around the mid-late 80's. This did not happen overnight, that's why you should go with the what it says on the actual hardware.

Although technically backward compatible per a Chrysler TSB with certain specific exceptions, transmissions originally spec'd for Dex will run a bit hotter on ATF+4. The best currently available fluid for those gearboxes is DexVI.

 

im sure dextron good for older tranys ran it in my 727
but the article was specific on 4 5 6 speed automatic transmissions my 518 is 1990-91
we have been typing about wat fluid to use dextron III , f type
well i just got my car off the stand s and took her for a test ride seems fine i will post the rest of the story on my BIG SWAP