i got a 1991 dodge 350 CTD with the 727 3 speed. whats the best trans fluid and what type of fluid does it take? (mercon 1, mercon 2, dextron....etc)

 

Dexron is the right fluid. If it's a tow rig, go synthetic.

edit: Actually, ATF +3 is the right fluid. If you can't get ATF +3, you can use Dexron.

 

i didnt know it but wal-mart sells mopar +4 tranny fluid, less than 5 a quart.

 

ATF +4 (or +3) is not suitable for 1st gen transmissions. There is a TSB from Dodge about it. Use Dexron.

edit: Actually, use ATF +3

 

ok got ya on that.

 

My '93s Owners Manual says clearly to use ATF +3 (now ATF +4) and NOT Dextron

 

Any more info on this TSB DAVE.
TOMMY

 

Actually it says to use Mopar ATF Plus (which is no longer available). You are correct on the ATF +3, I made a mistake. ATF +3 superseded the old 7176 fluid so it is the right stuff to use. Dexron is OK if you can't find ATF +3.

ATF +4 is still a no-no, though.

Click and read.

http://dodgeram.info/tsb/2004/21-004-04.htm

Our trucks are on the list, therefore they should not be filled with ATF +4.

This is why guys with stick trucks should stay out of auto trans threads.

 

I'd put some Dex VI in there if I could find it for a decent price. That's what's going in a 727 behind the 440hp in my '70 TnT New Yorker this summer.

 

I got TOTALLY confused trying to find a synthetic for mine . I ordered some AMSOIL "one size fits all" HD synthetic. I'll fill it when it comes in and I get the cooler installed. Seems like opinions on ATF are all across the board but from what I gleaned doing searches was that the new ATFs aren't backwards compatable for us because we don't have "electronically" controlled tranny's.

 

My comment wasn't based on opinion. The earlier Chryco trans were spec'd for Dex. The new synthetic Dex VI "is" fully backwards compatible. +4 is not backwards compatible for Dex applications due to the friction modifier characteristics of the fluid designed for the friction materials in the newer electronically controlled transmissions. That's fact, not opinion.

 

Hmm... After reading the following SAE tech publication on the subject, I'm rather convinced that +4 is the PREFERRED oil for the tranny. It would appear to have identical friction characteristics as +3 when both are new, but +4 is stable for much longer while +3 degrades.

http://u225.torque.net/cars/tech/trans/982674.pdf

 

Dangit! I HATE split decisions!

After more research (DTR/TDR/DTT), it seems there are more opinions on which ATF to run than @#$% bugs swarming my shop lights!

1/4 say ATF +3 = dang near non-existent around here
1/4 say Dextron X + Black LubeGaurd = ATF +3
1/4 say "Brand X" synthetic ATF = me thinks they're all selling it!
1/8 say anything from hyd. oil to engine oil
last 1/8th using flux capacitor drive

I just can't stomach putting the "wrong" ATF in and having my "new" sled lay down before I get to haul anything with it!

 

I find it a rather glaring omission the terms "727" and "A518" do not appear in that document. The only places the term "Dodge" appear are associated with electronially controlled minivan transmissions. I can't see why you would be convinced to use +4 fluid in the Cummins truck transmissions from reading this paper.

Did you read the TSB referenced above?

 

Your transmission was originally spec'd for Dexron II. Read the owner's manual, if you have it. Use Dexron. It is really just that simple. Dex VI is the newest synthetic Dexron formula available. The rest of that tripe, including a non-specific SAE paper, is just confusing hogwash.