The Dodge/Chrysler A604 ultradrive was also weak, as far as heat is concerned. That is easily
corrected with a larger cooler.
The problem here is, the cooler is all you have. So, idling without the fans on, temps
rise. Trans temps fluctuate too much with just a cooler. To fix this, you get a radiator
with a trans cooler. You run through that first, then through the trans cooler, which
is an AUX cooler now. Mount that trans cooler in FRONT of the A/C condenser, not
between it and the radiator.
The first thing I did with my 2000 Avenger ES, was add a medium duty aux cooler after the rad.
Ran that car 153,000+ miles, never had a transmission failure, and I towed a boat with it for two
years. The cooler, I mounted right in front, where cross-hair opening in the bumper cover was.
Mine had a warning right on the dipstick not to exceed 170- degrees, which was nearly impossible
with how they're set up from the factory. This cooler I added to this car is about the same
size as the factory mustang one on mine.
I had a 2007 Charger, and it had a separate, stand alone cooler like the Mustang does, except it was
over twice the size as this Mustang one. It was twice as high, and ran the length of the radiator, also
behind the condenser. Temps were great with this, except idle.
Mustang:
Replace the Rad with one that has the trans cooler hook ups.
Run the trans into the rad, then into a FRONT mounted aux cooler.
Factory cooler is about a medium duty, use a heavy duty cooler.
You can take temp readings now, then watch how they lower and stabilize with the
change.
OR, at the very least, replace the OE cooler with a bigger one, and mount it in front
of the condenser. You can even put a push aux fan on it, and use a simple temp
probe with relay to turn it on at 175 degrees or so.
170 degrees is where you want to be with any automatic. Mine averages 173 while
cruising, Has gone up to 180+ idle, 194 up hill with the fans off, and that's too high.
I Want to change the cooling to what I want, RAD then Cooler, but need to find the
rad that will fit...
JJ427R and I both have a 2010 GT automatic with the Roush M90 blower. He has the smaller blower pulley..with more boost. I have ceramic LT's, hi flow catted H, and a full 2.5" ID H, twin 62mm TB, + 94 tune. He has a tiny bit more hp.
On idle, the 5r55s will eventually get up to 120 F. Start driving... and eventually the 5r55s gets up to 170 F.... and stays put...doesn't budge. (winter or summer). Mash the gas on the hwy, blower on, down into 3rd gear... and tranny temps shoot up to 200 F.... in a mere 5-8 secs ! And this was AFTER I installed the same PA 2.1" deeper al pan..which holds an extra 4 qts of ATF. Also had switched to RP 100% synthetic ATF. And also a JDM catch can. Oem fubar upper grille tossed, and replaced with a 7 bar grille. Top rad cover is a mishimoto, which has an offset on front portion, which forces more air through the radS.
So in went the B+M 13K BTU tranny cooler, which is a bar + plate type, 3/4" thick... and sits directly below the oem 10K BTU tranny cooler. Plumbed so atf goes through oem rad 1st.... then the B+M rad. The B+M rads uses an integral T stat..which works on viscosity of the ATF.
OK, once the temp gets up to 170F.... stays put, doesn't budge. From 40-50 mph, Mash gas, blower on, down into 3rd gear.... and the highest it gets to is 171 or 172F...even at 120 mph..(in 4th).
In jj427r's case, he cut a portion of the front bumper...to get his 20.5 K BTU tranny cooler to fit. His sits in FRONT of the 18" tall x 21" wide Roush HE. But he's running on 4 mile road courses, look at his video's.... 137 mph. Blower is on for a huge chunk of each lap. He's either hard on the gas...or hard on the brakes.
He also has the 7 bar upper grille... AND hood ventS. His only option left is to install 1-2 13 k btu B+M coolers below OEM cooler. (then he would have a total of 43.5 to 56.5 K BTU).
I looked at those tranny coolers, that reside at base of eng rad...that u spoke of. They are integral with the eng rad. They also result in a net loss of eng rad area.
IMO, their only advantage is to get the ATF up to 170 F faster. The coolant in the eng rad portion is 205-220 F. That's not gonna help cool atf any time soon. Moot point, since none are available for the 05-10 auto GT's.
The eng fan IS on high speed mode. The low/high speed oem eng fan threshold is fully adjustable via the SCT X3/X4. Any time you have air coming up through the very top vent...(next to glass).... the eng fan on a 2010 defaults to high speed anyway. (regardless whether AC is on..or OFF... and Regardless of speed of cabin fan. On idle, in driveway, the air just screams through the 7 bar upper grille.
Real fix would be to replace oem auto tranny cooler.... with a bar+ plate type... that is the same width as oem...or slightly wider...... but full height top to bottom. I calculated 50-52K BTU. But they don't exist...... would have to be a custom build.