Quote:

I learned the hard way NOT to use ATF +3/+4 in two of my past cars:
1) '71 Charger SE 383 hp with mild rebuild (425 HP gross), 727 and 3.23 one-leg ... burnt tranny up 500 miles after broke in the engine , went to Hughes TC and trans rebuild and Dexron II and no more problems.
2) '74 Dart Sport 360 with mile rebuild (298 rwhp) and 3.91 sure-grip and 727 ... burnt tranny up within 1000 miles of engine break-in , went to Mopar 175K TC and trans rebuild using ATF +4, had to REDO trans within 400 miles as it already had "black death" in the fluid!

Both trannys were serviced @ Chrysler dealership I worked at prior to engine rebuilds, both had ATF +4 put in 'em and toasted both even with tranny coolers in already! Rarely power-braked either one as they both broke loose from a dead stop quite well ... just my worth.
No old in new, no new in old anymore for me ... Imperial doing great w/Dexron in it.



Sorry you had trouble, but I hate to say it, your problems weren't fluid related. The ATF 3/4, and Mercon V(which has synthetic properties and I like, btw), can be substituted for Dexron with NO consequences. It's the other way that you will have problems. Put Dexron in a late model Ford or Chrysler and you will certainly have lockup clutch chatter, along with a host of other problems.

As a trans shop owner, I attended seminars on transmission fluid composition, and reps from Borg Warner and Raybestos( the major players in clutch mfg.), were there and gave us the skinny on what works and don't work. Believe me, a non lockup Torqueflight will perform perfectly fine on just about any fluid you put in it. I say if you are running a high HP motor with a high stall converter, look into synthetics.

I run Mercon V in the trans I built for a members FAST RR. All season long, made every race no issues whatsoever.

Mike

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