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Tranny cooler

Discussion in 'The Garage' started by Tshane, Sep 14, 2003.

  1. Tshane

    Tshane 1/2 ton status

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    Putting an aftermarket tranny cooler on i was just wondering what you guys think i should do about the old one that is in the radiator. Still use it and run through both of them or just elimiate the radiator one?? If i should still use the old one should i run through it first or second?
    Thanks /forums/images/graemlins/truck.gif
     
  2. big pappa b

    big pappa b 3/4 ton status

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    Just leave the old one alone. It should relieve a lot of heat so your engine coolant will cool better
     
  3. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Keep in mind that during the winter the in-rad tranny cooler becomes a tranny warmer.....

    Most of the literature I've read regarding the installation of auxilliary tranny coolers recommends that your run your aux. cooler along with the factory cooler.
     
  4. heavy4x4

    heavy4x4 1/2 ton status

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    Use both. Plumb the aux cooler into the return line (top fitting on the radiator w/ a 700R4).
     
  5. Pookster

    Pookster 1/2 ton status

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    Im running 3 tranny coolers- the inside radiator one, the factory auxilary one, and then a 10,000 Hayden stacked plate. Why 3?

    #1: removing the factory auxliary one was a pain in the !@#! No way for me to get to it without removing my winch and my grill.
    #2: Even more cooling. 1 is better than none, 3 is better than.. 2?
    #3: In the winter I can just use a piece of heavy plastic and cover the third one, thereby providing almost the same temp as without. having it there.

    I had started considering whether or not the "Extra" cooler would have extra resistance throught the system, thereby acutally decreasing the cooling effect. I took the hayden, and just blew through it with my mouth. It had virtually no resistance. This I felt comfortable that the overall increase in distance in cooling was no more than the lenth of the cooler and the extra hose used (which added up to about 16". Any fluid speed loss was acceptable, as the stacked plate tranny cooler radiates a lot of heat!
     
  6. Judd

    Judd 1/2 ton status

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    If you are not running your AC and still have your condensor,,use it. I have my fluid going to my radiator cooler then to my AC condensor and back to my tranny. I live in Ga. and I'm no too worried about the tranny oil being too cool. If once I install my gage and it does not get to temp. in the winter, I may re-run my lines. It was just a heck of alot more convienent to run it as I have it now.

    I have not had the time yet to install my temp gage {with-in a week or two} but it seems to work well. Tranny shifts fine {I was worried at pressure loss through the condensor} and the line out of the condensor is alot cooler to the touch than the line going in.

    The Blazer already had a medium size after market tranny cooler on it when I bought it. I used that cooler for my P.Steering.
     
  7. DBLAZER

    DBLAZER 1/2 ton status

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    Keep both of them. COOL = GOOD[​IMG]
     
  8. ntsqd

    ntsqd 1/2 ton status

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    [ QUOTE ]
    Use both. Plumb the aux cooler into the return line (top fitting on the radiator w/ a 700R4).

    [/ QUOTE ]

    I plumb them the other way. My logic is that I'm buying the largest cooler I can fit on/in the vehicle. I want the trans fluid cool, but I also want the trans to warm up enough to boil off any condensation in the fluid. By going thru the aux cooler first I've a reasonably good idea it cooled the fluid. Then by going thru the radiator cooler I know that if the fluid is too cool (winter driving other than in So. CA) that it will get warmed up. The only thing is that the fluid needs to be replaced more often when plumbed this way because all of those heat cycles accelerate the degradation of the fluid. ATF is a wear item, the trans is not.
     
  9. 88Silverado

    88Silverado 1/2 ton status

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    [ QUOTE ]
    Then by going thru the radiator cooler I know that if the fluid is too cool (winter driving other than in So. CA) that it will get warmed up.

    [/ QUOTE ]

    Trans fluid needs to be warm. Min fluid operating temp is around 175F. Many trans shops and I believe GM recommends it being setup this way (external cooler first, then warmed up via radiator cooler). I use to think the other way was best but im learning different.
     
  10. heavy4x4

    heavy4x4 1/2 ton status

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    I appreciate your thought inspiring comments, guys, but honestly I wouldn't set mine up differently. I run a pretty consistent 155-170 in the pan. The transmission acts just fine at that temperature.

    [ QUOTE ]
    Min fluid operating temp is around 175F

    [/ QUOTE ]
    Please, explain your reasoning behind this. Trans fluid is just a means to create pressure, who cares how low of a temp it's at. All you have to worry about the ATF (or any fluid) is that it doesn't boil (create compressible gas).

    Also, here's my take on the idea of the radiator heating it up after it goes through the auxillary cooler first. When the vehicle is cold (under operating range of 180, 195, or 210), no warm antifreeze is going through the radiator, so it's not heating up the trans fluid then. And, once it does go into a radiator with coolant that's at 180 degrees, it would pick up not much more than a couple of degrees...probably lose most of that increase on the way back to the tranny through the cooler lines.

    So, although I like the different ideas and approaches of looking at the tranny cooler situation, I'll stick with the way mine is set up and continue extending the life of my transmission.
     
  11. ducttape114

    ducttape114 1/2 ton status

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    for those of you running the AC condenser as a tranny cooler, how the heck do you flush it? i need to flush mine but since the input and putput are both at the top i worry im not gonna get everythign out. maybe i should just pull out and lay it flat to flush it. or push the truck on its side /forums/images/graemlins/smile.gif
     
  12. 88Silverado

    88Silverado 1/2 ton status

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    [ QUOTE ]
    Please, explain your reasoning behind this. Trans fluid is just a means to create pressure, who cares how low of a temp it's at. All you have to worry about the ATF (or any fluid) is that it doesn't boil (create compressible gas).


    [/ QUOTE ]

    All fluids are designed to work at certain temperatures. ATF is designed for a nominal 175 with a +/- range. As the fluid cools or heats, its viscosity changes, the fluid shear levels change and so can the lubricating properties and potentially shift quality.

    At higher temps,(mid 250's, way before ATF boils), the fluid will start to oxidizes, it turns brown and takes on a burnt smell. The heat destroys the fluids lubricating qualities and friction characteristics and varnish begins to form which interferes with the operation of the transmission. This is way before it boils and creates compressible gas. So it does make a difference how hot or how cold the fluid gets.

    Now, most external "air" type coolers are only 30-50% efficient (which is actually better than the radiator coolers around 20%). In most driving conditions, with the external cooler last temps may drop within the 60-100* range. This is within the operating temps of the ATF. In severe cold (single digits or negative outside temps) the fluid can start to approach min temp levels affecting the trans.

    The only thing running thru the radiator cooler last does is provide a thermostatic effect, or nominal temp for the fluid and helps keep the trans operating at a more constant temperature.
     
  13. Judd

    Judd 1/2 ton status

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    [ QUOTE ]
    for those of you running the AC condenser as a tranny cooler, how the heck do you flush it? i need to flush mine but since the input and putput are both at the top i worry im not gonna get everythign out. maybe i should just pull out and lay it flat to flush it. or push the truck on its side /forums/images/graemlins/smile.gif

    [/ QUOTE ]

    Yep, take the the condensor out! It's a heck of alot easier to work with. /forums/images/graemlins/thumb.gif

    I just used a electric fuel pump and pumped lacquer thinner though it for a while {maybe 10-15 mins.}. I ran both lines into the same container and let it run. Once I thoought it was flushed enough, I ran one clean gallon of cheap ATF through it.
     
  14. rcpilot

    rcpilot 1/2 ton status

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    How about for those of us that live in the desert south, where the temp never goes below 60, just running only an external/aftermarket cooler, no radiator routing. /forums/images/graemlins/thinking.gif
     
  15. 88Silverado

    88Silverado 1/2 ton status

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    Good question....
    I live in the desert north where it can get into the teens and sometimes single digits in the winter. My K5 Only has the external cooler, it does not route thru the radiator. I know the factory fan pulls alot of air and I have "felt" the fluid in mine after long drives and doesnt feel very hot to the touch. Have also checked it in the winter and it barely feels warm. I dont know if someone changed out the radiator or if this was factory...sure looks like factory plumbing to me. /forums/images/graemlins/confused.gif

    Again, were talking about "cold" temps, in the zero to negative range outside. Most fluids can and will work in the low temps. 99.9% of the problems occur when too hot. Just different philosophys by the mfgs on how things are plummed up /forums/images/graemlins/thumb.gif
     
  16. chosen1

    chosen1 Registered Member

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    My friend did bypass the radiator cooler and ran only a a aftermarket trans cooler on his 70 Buick Skylark, after a 30 mile ride from Milwaukee to Racine somewhere, The trans fried! /forums/images/graemlins/angryfire.gif /forums/images/graemlins/1zhelp.gif
     
  17. rcpilot

    rcpilot 1/2 ton status

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    I know Mike from ECHOBIT has been running only a cooler on his for quit some time...as we all know he has wheeled the h**l out of his truck.. and has had no problem. /forums/images/graemlins/thinking.gif
     
  18. Chris_T

    Chris_T 1/2 ton status

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    When my dad had an RV shop install his trans cooler they did it with a thermostatic switch/valve in the cooler lines. The fluid bypasses the external cooler to keep it warm (lives in Canada) until the fluid gets hot, then it runs through the cooler. Seems like a good idea to me, doesn't overcool the fluid, still lots of cooling ability, I just haven't looked for the switch/valve yet.
     
  19. SUBFAN

    SUBFAN 1/2 ton status

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    IIRC, Bowtie Od's sight says the optimal temp in the pan for a 700R4 is 150*....How does this affect things?
     
  20. 88Silverado

    88Silverado 1/2 ton status

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    Thats based on BTOD's measurements on several cars.
    In fact, to get their warranty, they want you to measure the fluid temp. They feel the 150ish in the pan means the fluid isnt getting cooked in the converter and theres sufficient cooling. They will recommend you run an external cooler over 185. On my 71, with a 2200 stall converter, depending on the time of year and how hard I drive it, mine will range from 100-185. (the 185 is when the fluid is up to the radiator water temp from the internal cooler).

    I posted somewhere before but heres kinda a breakdown of mileage on fluid versus temp:
    As a rule of thumb, every 20 degree increase in operating temperature above 175 degrees F. cuts the life of the fluid in half. The approximate life expectancy at various temperatures is as follows:
    175F 100,000 miles
    195F 50,000 miles
    212F 25,000 miles
    235F 12,000 miles
    255F 6,250 miles
    275F 3,000 miles
    295F 1,500 miles
    315F 750 miles
    335F 325 miles
    375F 80 miles
    390F 40 miles
    415F Less than 30 minutes

    Remember the temp in the converter is usually much higher than the pan, usually in the low to mid 200's. If your running a higher stall converter, the temps can be much hotter. Thats why its suggested to change every 12,000-25,000 miles.
    I know people who never service their transmissions and dont understand why they fail about 75,000 miles.

    Everytime you change your oil, pull the trans dipstick, look at the color and smell it. If its brown and smells burnt, do a flush ASAP. If not...dont worry about it and change it about every 2 years max. A case of fluid and filter kit is under $25. Cheap once-a-year service.
     

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