Transmission Temperature

Discussion in 'KK General Discussion' started by David13, May 2, 2021.

  1. David13

    David13 Full Access Member

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    I went for a drive up a canyon road, off the pavement and up to the snow and wet road.

    I'm trying to get my trans refill level right.

    Going up, I went up maybe 2000 to 3000 feet in 8 or 10 miles. Steep, steady uphill, the engine went up to about 217.

    But the transmission temperature got up to 240. Then started down as the altitude gave lower ambient temps, down to 54 or so.

    I may remember someone who watched their temp and didn't like it when it got too hot. I don't remember what that temp was.

    I also don't recall, didn't really look if the kk has a transmission cooler. I want to pull a trailer up that, and other canyon roads. Trailer 725 pounds and atv 600 or 700, so 1300 or 1400 pounds.

    Do I need to add a trans cooler.

    If so, what's a good brand to add.

    I'm missing the mechanical fan and clutch. That will offer engine cooling, but not trans cooling, will it.

    Thanks
    dc
     
  2. Hunter Toth

    Hunter Toth Member KJ Supporting Member

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    I run 32s without an axle regear on my KK

    It was getting a little too hot while offroading
    The "crawl home" mode and trans temp indicator light comes on at 270

    I had that light come on, and after that did all the research I could

    From what I've gathered, the KKs trans cooler is part of the AC radiator, so its in front of the engine
    Instead of trying to add an aux trans cooler, I added the HD cooling fan and life has been GREAT!

    It also helps to put it in 4low or put the shifter in "2" or "1" to reduce powertrain stress and constant shifting

    This thread had a lot of great info on the HD cooling.

    Also as a tip, I installed the fan from underneath after removing the sway bar
    It takes two people, one up top and one under but it worked great and saved a lot of time
     
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  3. David13

    David13 Full Access Member

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    What I have found so far.

    Some Libertys came with a trans cooler as part of the radiator. Not mine.

    Mine probably came with (tow package) a trans cooler as part of the a/c condenser.

    I have to lines underneath that seem to come from the trans and are just looped into each other, moving from the drivers side to the passenger side at the front of the engine. It doesn't look like they were mickey moused into each other, but that they fit together well.

    I'm assuming there was a leak in the trans cooler, so they by passed it in this manner.

    Or, in replacing the a/c cooler, they ended up with being sole one without the section for trans cooler, so they by passed it in this manner.

    So in remedy, I have two choices. One, get a trans cooler/a/c condenser oem and open up the a/c to switch it in.

    Or, just add a trans cooler in front of the a/c condenser and plumb it into the two lines.

    One thing I don't think I wast to do is put in two trans coolers.

    Another thing I may need to try is monitor trans temperature going up the same canyon road in 2, rather than drive. See how much of a difference that makes.

    Also just monitor trans temp on a level ground drive.

    And, I am missing the mechanical fan and clutch. So I have to add that.
    dc
     
  4. lfhoward

    lfhoward Full Access Member

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    DC, I was the one who had the transmission temp issue last year. Here is the thread.

    https://www.jeepkj.com/threads/transmission-temp-scare.75495/

    It got up to 268°F. I installed an aux transmission cooler in front of the radiator and haven’t had any trouble since. (My Jeep already had the HD cooling fan.)
     
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  5. David13

    David13 Full Access Member

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    Thanks Howard

    There was also a more recent thread on the mechanical cooling fan and installation of it with model numbers, etc.

    I'd like to reread that one if someone can find it for me.
    dc

    I think I'm settled on the Hayden 2736. I just need a fan blade to go with it.

    I'm going to take off the grill tomorrow and find what size cooler I could locate somewhere on the front end. I think I was the biggest I can find. I will do a fluid fill measure then add that much fluid when it's in.
     
  6. David13

    David13 Full Access Member

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    Well, to add any fan and clutch I should take off the shroud and the over flow box. And if I do that I can then easily access the water pump and lower hose, and thermostat.

    And then maybe I can determine what all those hoses down there are for. I see what looks to be the power steering going to a 3 or 4 inch by 12 inch cooler located low in front of the radiator.

    It appears that the transmission lines go to the side near the top of the radiator. There are two lines going from the a/c to the a/c condenser in front of the radiator. But the two looped lines across the front of the front cross member go up into metal tubes and I have yet to see where they go.

    Maybe they went to two other lines that went to an auxiliary cooler that was removed.

    I have reason to believe that the trans over heat light on the dash goes on at 270. I'd like to confirm that.

    But that means my trans had not yet overheated even tho I was straining it rather good on the steep uphill miles.

    So maybe I need to do some monitoring on regular down the highway miles. See where the temperatures go.

    But I'm thinking maybe while it's open an oem thermostat will be good, and a water pump.

    I'd like to avoid the plastic one. And ideas on that?

    Thanks.
    dc
     
  7. David13

    David13 Full Access Member

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    I'm wondering how I can test the by-pass valve in the transmission line.

    Any ideas?
    dc