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Thread: Trans cooler

  1. #1
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    Question Trans cooler

    Hello, The trans in my 95 k3500 runs border line hot when towing, about 240. My water temp gets up there too, ordered a radiator today. It has all the 2000 6.5 cooling stuff on it with a new fan clutch.

    I noticed that there is a trans cooler right behind the grille, looks factory, but trans oil don't go into cooler in radiator. Is that the normal setup?

    I bought a cooling fan that is made to go in front of condenser on left side, but the trans cooler is mounted there so no place for the fan.

    Engine oil cooler is on the right side, also no engine oil cooler in radiator.


    My thinking is the hot trans oil in radiator cooler would make the engine cooling more of a problem. I am thinking of adding another trans cooler.

    Tom
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  2. #2
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    Is there any dirt and trash between the stack?
    "The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government."
    -Patrick Henry


    A5150nut
    2006 K3500 D/A
    94 6.5 4x4 5spd Sold

  3. #3
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    Arrow

    Generally, electric auxiliary cooling fans do more harm than good by blocking airflow. And, they aren't needed if everything else is OK.

    Remove the top half of the fan shroud, and look between the radiator and A/C condenser. See any accumulation of leaves or airflow blocking stuff?

    Does your fan-clutch ever engage. The roar is unmistakable. Should happen between stoplights in town on a hot day, or anytime engine coolant temp exceeds 210.

    If your radiator is original to the truck, it likely needs to be replaced or at least serviced (cleaned and flushed on the inside and outside). The plastic end-tanks are removed/replaced during a service.

    Jim

  4. #4
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    The oil cooler that is divorced from the radiator is a standard set up on some rigs
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  5. #5
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    I have the new radiator in. I washed out the condenser and oil coolers. They were pretty clean anyway. I need to hook it to my trailer to see if its better, hot and muggy here so it will be a good test.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  6. #6
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    New radiator helped. Trans temp still goes way up. I got a new filter for trans today, have not changed it yet though.


    On a 95 will hi trans temps cause it do defuel?
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    Last edited by 94GMC2500; 06-28-2018 at 13:55.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  7. #7
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    High trans temp will not cause a "defuel". Maximum trans temp will (260+), and cause limp mode (SES will be on). Yours is too hot for normal duty. You shouldn't see it that hot unless towing a long grade in very hot weather. Make sure the torque converter is locking. If it isn't, it will heat up high and quick under moderate to heavy loads.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  8. #8
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    My recollection is there is an air to oil cooler as well as the water to oil cooler, at least on mine with the tow package. Is that the case here?



    (Of course, have you confirmed the accuracy of the gauge?)
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    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  9. #9
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    The trans goes to a good sized cooler in front of radiator but not connected to the radiator trans cooler. I put new filter in this morning pan was spotless inside so I assume someone else has had the pan of not to many years ago.

    I went for a easy 20 mile ride not towing anything and trans temp said a little over 200, in 85 degree muggy weather. Trans temp gauge sender is in test port on side of trans.

    I held a thermometer on a stick on the bottom of pan and it said 185 just sitting there idling in park for about 15 minutes.

    The images show the normal water temp driving it easy and the trans temp from this mornings easy drive.

    Do the factory coolers plug easily? The inside I mean.
    Attached Images Attached Images
    Last edited by 94GMC2500; 06-29-2018 at 09:41.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  10. #10
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    Mine was definitely connected to both.
    The Constitution needs to be re-read, not re-written!

    If you can't handle Dr. Seuss, how will you handle real life?

    Current oil burners: MB GLK250 BlueTEC, John Deere X758
    New ride: MB GLS450 - most stately
    Gone but not forgotten: '87 F350 7.3, '93 C2500 6.5, '95 K2500 6.5, '06 K2500HD 6.6, '90 MB 350SDL, Kubota 7510

  11. #11
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    I drove truck again to day, just a normal drive, not towing anything, 94 and humid out.

    Trans temp said 210, I crawled under with a temperature gun and checked side of trans, 202 degrees, side of pan 185, hot side of cooler in front was 185, cool side of cooler was 176.

    The sender is in the test port, is it better to have it in the pan or test port?
    Last edited by 94GMC2500; 06-30-2018 at 14:00.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  12. #12
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    What does the IR temp sensor say about the location of the test port? The sender could be indicating non-fluid heat, which is OK. Part of the fluid's job is to remove heat, which it appears to be doing.

    It is better in the pan or the outlet to the cooler, but doesn't matter where you put the sender. NONE of the temp data is good for anything other than tracking trends. Senders and gages are notoriously inaccurate, but should be linear with actual. As long as the value is linear with actual conditions, assign that as "normal", and track the trend from there. Or move the sender and feel better about it.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  13. #13
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    I am going to add another cooler since I have one laying here and move sensor to the pan and it is what it is I guess.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  14. #14
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    I would suggest doing one at a time. First, move the sender. See what you really have. Then, add the additional cooler to maximize the cooling ability. Doing both will not tell you what was the problem, if there was a problem.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  15. #15
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    In past years when I was towing I had a gauge reading the fluid temp at the inlet of the cooler and a second gauge reading the temp at the tranny return port.

    Temp of the fluid in the converter is the important issue.

    If the converter is COOKING the fluid to 220-250 F but your cooler is bringing the temp down to under 200 F the cooler is working, but the fluid is still being fried....

    Are you sure the converter lockup is functioning ???


    Snap a piccy of the tranny cooler that's there now and post it please.

    The test port is just that...A pressure test port.... and it is the end of a passage.

    You need the temp sender in an area that sees fluid flow and not a place that is surrounded by metal in close proximity (Port passageway)


    Get your setup so the gauge sender is in moving fluid...

    The pan is nice....but as I mentioned having data on what the temp is pre cooler and post cooler is a good thing...
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  16. #16
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    When I am driving along at 60 mph without the cruise on and I touch the brake pedal the rpm goes up so I assume the converter is locking up.

    I don't think I can get a decent pic of the cooler without removing the grille but I will try. It looks like the factory cooler to me. Cooler is about 11x6 inches.


    The second cooler is the other one I have, 14x7.5 inches.
    Attached Images Attached Images
    Last edited by 94GMC2500; 07-01-2018 at 07:45.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  17. #17
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    We do garden tractor pulling and I pull a 28 ft pace trailer. I wish I could get this truck so I can just go pulling and not have to worry about it over heating or if the trans is really getting to hot. I ordered a couple 180 T stats from SSDiesel, I figured it cant hurt.


    I dread going up a good sized hill in hot weather, truck heats up and has no power in warm to hot weather, some times 45 mph is all it will do on hills with the trailer.


    It has 4.10 gears, new diamond eye 4 inch exhaust, walking J computer chip, manual boost control, all the late model 6.5 cooling stuff, new radiator, HD fan clutch, newer lift pump.

    On a hill with it floored at about 12 lbs of boost on a hot day I get no smoke out the exhaust at all, but EGT pre turbo will go to 1250 if banks gauge is right.


    I am thinking of trying a holley red pump for a lift pump to get more fuel pressure going into injection pump.


    The engine might be tired and don't know how good the pump and injectors are.


    I have done diesel work on tractors, rebuilt a 8.3 cummins last winter, rebuilt many older IH and JD diesel engines, so I am some what up on diesels, I don't think the engine in my truck sounds to bad yet, more blow by than I would like though.


    I am just venting a little I guess.


    Tom W
    Last edited by 94GMC2500; 07-01-2018 at 12:07.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  18. #18
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    What is the gross weight of the complete outfit (T&T) and the loaded trailer weight ???


    The 1250 F EGT number makes me waaaaaay nervous.

    1000 F is about the max safe number to run a 6.5

    Is the Pyro in the exhaust PRE or POST turbo

    Pre turbo should see no more than 1000 F on a hard pull...

    I have never heard of the Chip maker you spoke of..
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  19. #19
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    Pre turbo, probe is in exhaust manifold under the turbo. KOJO tune chip. I don't know what the total weight of truck and trailer is. A guess on trailer weight is 8500/9000 lbs. Trailer pulls hard in my opinion. Maybe ex temp gauge is way off, no idea on how to check it.
    Attached Images Attached Images
    Last edited by 94GMC2500; 07-02-2018 at 07:23.
    1995 K3500 Silverado extended cab dually auto trans. Diamond Eye exhaust, KOJO chip, manual boost control, HD cooling, PMD behind bumper, modified fan clutch.

  20. #20
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    Copy on the weight.

    That flat front trailer is like pulling a barn.

    Huge frontal area.

    8000# on a grade behind the Burb is going to be a hard pull.

    The Burb is 6000 to 7000 #

    Close to 15K COMBO

    Given the engine is likely in the 250 HP range and then add the heat issue...

    It takes serious HP to yard that kind of weight around..

    What sort of grade percent ???? 5% or greater ??
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

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