5150cliff

After listening to many differing opinions on how to prevent the overheating of the trans on the jk-auto transmission, I have put in an aux-cooler to help. My question is this...
1) Does the torque converter slip in drive until it reaches 3rd gear, causing heat build up?
2) If I put the trans in 1st gear while going up a steep hill, does that put the torque converter into the lock position even in 4-high?
3) Or does the torque converter only lock up in the 4-low transfer case position?

I suppose I'm getting at this.....which position in the trans is best for not slipping the torque converter and thus not generating any heat built up that will ultimately cause the 'hot-oil' light to go on?

JKlad

Yeah, it locks up when it gets to third, and the quickest way to get it there offroad is to run in 4-low. Most heat build-up issues people have offroad are caused by running in 4-hi and making the torque converter do all the work instead of shifting to 4-low & letting the reduction gearing in the transfer case do its thing as its designed to do. I've even heard guys on the trails saying that us 6-speed drivers are all a bunch of pussies for changing down into 4-low and boast that they can do it all in 4-hi; that is until you see them stopped further down the trail with smoke billowing out from under the hood from where the ATF has boiled over and started smoking like crazy on the red-hot cats.

ronjenx

What JKlad said!

I've done lots of testing on that technique, and can actually see the temps fall when I drop to 4lo, selector in "D", O/D off.
Turning on the A/C will force the fan to come on well before the transmission temp calls for it. Haven't tried that in the winter, though.

And a transmission temp gauge should be installed so you can see what's going on; either an AeroForce gauge, or an old school probe-in-the-pan gauge.

But, installing a cooler will greatly increase the margin of safety so you won't have to worry so much about temp.

5150cliff

Well, that's exactly what happened...up a steep hill, in the snow and slush in 4-hi.....took about 10 minutes for the oil light to come on. I really appreciate the info. One last thing....is it possible to do something to the computer to make the trans lock up the converter in any gear you want? Or am I dreaming?

mjm

What is best way to keep the trans cool when 4lo is not needed? For example climbing dirt roads in the mountains when speeds are a little too high for 4lo to be used. I know that a cooler would help, but what about technique?

ronjenx

Are you talking about fast enough for the transmission to get to 3rd in 4 hi? By then there is plenty of air going through the cooler. The temps will be higher than on the road, but I've never overheated under those conditions.

The best way is to install an aux cooler. I haven't needed to yet. It will happen eventually.

mjm

Mine overheated in 2hi D\w OD off climbing up a dirt road in the mountains. I was going pretty slow... As soon as the warning light came on I put into 4lo and the warning light turned off in about 2 mintues. I stayed in 4lo for the rest of my off-road trip without issue. I wish Chrysler would fix this problem with a proper TSB.

ronjenx

Yup. You must not have made it to 3rd and T/C lock-up.

There is a kit out there which allows 2lo to be a selectable position. That would really ease the strain on the torque converter.

foverorubi

i havent tested this yet but, will the rock crawl tune on the superchips help bring the transmission to 3rd sooner?

Fenrir

Let me preface that I have NOT read this entire thread... (in a rush, wanted to just ask this question before my meeting starts here at work)

Shame on me!!!

I've been emailing AEV about getting some stuff/installed and I asked if they could go ahead and install my B&M Supercooler. They claim that I don't need one as my Auto already has a transmission cooler.

Who's right here? Does it have a cooler already and the B&M Supercooler is simply an Auxillary cooler?