Tranny cooler

JKFlyer · Jul 3, 2014

Jiblet said:
The 3.8 auto trans practically requires an auxiliary cooler. The B&M model mentioned is very popular and easy to install. You can find good installation write ups easily. Just be sure to plumb the lines trans > stock cooler > aux cooler > trans.

Mopar sells a really nice fitted kit, too, but it's a couple hundred bucks more than the universal ones.

The B&M 70268 does a great job. I've run one for 5 yrs now on my 08. I was horrified that I was seeing temps well over 200 in traffic and on mountain roads. I haven't seen 180 with the cooler.

If you run a 3.8 without a cooler, check your ATF for darkening (should be bright red) or any hint of burnt smell. ATF+4 are all the same and can be found for ~$5 per quart.

This x2. I have trail dash always showing trans temp and mine dropped from 180-225 range to 130-170 range. No joke. Once I regeared, even lower.110-140 ish

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Fitzbsly · Jul 3, 2014

I got PSC dual cooler, trans and steering. Easy install, maybe 30 min. 30-40 degree drop aft install.

Jiblet · Jul 3, 2014

Moochie said:
Yes, the stock tranny cooler is located at the bottom of the AC condenser.

Correct. All auto trans JKs come with a factory cooler. But the one on the 3.8s under performs even for DD or mall crawlin.

Jeep's solution was the J30 recall to add the HOTOIL warning. I'm told the warning triggers at 240°.

MurderedJK · Jul 4, 2014

cozdude said:
stupid question but dont jeeps after a certain year (08 or 09) already come with a tranny cooler at the bottom of the radiator? just curious is my 2011 already has one?

Yes they do. The bad part about this though (after original tranny died at 28K) is that not enough air can get to it. My dealership told me that it was a poor design which really limited the air to the trans cooler. In the case of my dead tranny, I limited that already limited air flow by putting a winch on the front bumper... Lessoned learned and I ended up having the dealership put a mopar cooler in at the same time they replaced my tranny under warranty.

Dune Crawler · Jul 23, 2014

Skeem47 said:
The install was super easy. I was a bit skeptical at first but went for it and it turned out to be way easier than I thought it would be. I'd say the hardest part was getting it mounted and figuring out how to use the brackets to get it straight while keeping a bit of space between the cooler, the bolts and the radiator.

The difference in temperature was almost instantaneous. Before the install, I started up the Jeep for only a few seconds while I went underneath to find the transmission lines. One should be a bit cooler to the touch. Well, both of them were almost so hot I couldn't touch them at all. After the install however, I drove from Tempe to West Phoenix, parked and went underneath to check for leaks or anything out of the ordinary. I touched the lines to see if there was a temp difference and I could actually hold onto both lines without burning my hands or it getting too hot I had to pull away! I couldn't believe it and I still can't lol. This was also done in January and I wouldn't touch anything underneath there at this time of year. Shit, you can't even touch the steering wheel lol. At the time of install I was running stock gears with 35's. The cooler was totally worth it!

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I'm having the same issue with figuring out which line is cooler by the touch. Did you use the bottom line? I think it's "the return" but both are so hot I was just assuming by the amount of fluids rushing from the top line compared to the bottom line.

Edit: got the B&M super cooler

Life's a beach

Dune Crawler · Jul 24, 2014

I can see instant real time trans temps from inside the jeep and this is what I got before and after install. (The time of driving was about 10-15mins same route.)

Before install:7/23/14
Max-167
Starting temp-116

After install:7/24/14
max-136
starting temp-117

I have a cat back and it also softened the sound.

Life's a beach

Tranny cooler

JKFlyer

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Fitzbsly

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Jiblet

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MurderedJK

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Dune Crawler

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Dune Crawler

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