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Tranny cooler

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 89Jimmy, Aug 17, 2000.

  1. 89Jimmy

    89Jimmy 1/2 ton status

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    I am installing a tranny cooler on the '85. The book says to feel the lines at the radiator and cut the cooler one to hook to the cooler. The lower line feels slightly cooler after startup but is hard to tell. Does anyone know if the lower line on the radiator is the outlet? thanks.
    John

    So Much to do, So LITTLE cash.
     
  2. ggallin13

    ggallin13 1/2 ton status

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  3. 90K5

    90K5 1/2 ton status

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    The lower line is the outlet but it doesn't matter if you run it to the cooler and then to the radiator or vice versa. I had to go to the cooler first on mine because the bottom one wouldn't stop leaking for some reason. Also dont use the zip tie mounts that come with the cooler just make some brackets or use stronger zip ties around the tubing and put them thru some holes that are already there.

    90K5
     
  4. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Hey 90K5- have you had problems with the mounting ties? I used the ones supplied with the cooler, and haven't had a problem. That was 7 years ago!!!! Just curious........
     
  5. DMK

    DMK 1/2 ton status

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    The cooler should be placed after the radiator cooler other wise the fluid won't cool down as much. It won't hurt anything but more cooling the other way. The radiator cooler only cools down to engine temp but the aux cooler will cool down further because it is not in contact with the engine coolant {water}. Also did make my own brakets out of sheet metal. Hope this makes sense.
     
  6. dumbfounded

    dumbfounded 1/2 ton status

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    The cooler should ALWAYS be on the "inlet" of the radiator. Do it the other way and your tranny probably won't last very long. If it is on the outlet it can run "too cool" which is detrimental to the tranny. So cool it before it gets to the radiator so if it is "too" cool then the engine heat will bring it up to normal operating temp.....

    Love, Peace, and Hair Grease...........
     
  7. DMK

    DMK 1/2 ton status

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    What is the point of the cooler than. Don't know anyone who runs one like this. Also the instructions in an b&m cooler says to run after the radiator, all trans cooler instructions say this. Even factory trans coolers are hooked up like this. Trans coolers hooked up by tranny shops are one this way also. Mine has been like this on every vehicle I have owned no problems.
     
  8. dumbfounded

    dumbfounded 1/2 ton status

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    This is coming straight out of trailer life. If you need to put it after the radiator what's the sense of even keeping it going through the radiator, kind of defeating the purpose. How about when temps are extremely cold outside? Your tranny would never warm up to normal temps since there is no thermostat on the tranny. And under extreme conditions putting it after would put an extra load on the engine coolant. Who knows maybe it depends on driving style and location.

    Love, Peace, and Hair Grease...........
     
  9. dumbfounded

    dumbfounded 1/2 ton status

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    Plucked around the net for some answers so here it is.

    Under normal driving conditions having the cooler after the radiator provides a tad more efficiency. This is for cars/trucks with stock thermostats. The transmission operating temp is 160-200 degrees. If your engine runs hotter than 210-215 then after is preferred. If you run a lower temp thermostat say 180-160 then before to maintain the 160-200 degrees. There is such a thing as over cooling with a transmission, just like an engine. Tolerances are closer therefore more wear, even more if you hot dog it. Just like racing a cold engine. Also if your tranny is out of temp range the shifts change b/c the fluid thickness is different. Hope this helps.

    Love, Peace, and Hair Grease...........
     
  10. DMK

    DMK 1/2 ton status

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    You have a good point, could also depend on were you live. Texas as opposed to Canada.
     
  11. Casey 86K5

    Casey 86K5 1/2 ton status

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    I have my cooler hooked up after the radiator. The trans temp will never get above 150 in the winter time, but during the summer it will sometimes go over 200. What should I do about the over cooling problem in the winter? I dont want to keep switching my cooler lines all the time. I also do a lot of heavy towing.
     
  12. talldogg

    talldogg 1/2 ton status

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    Casey,
    They sell aftermarket thermostats for trannys. From the picture, it appears you place it some where along the lines. It was cheap, and it works the same way a regular thermostat does. I forgot where I saw it. It was either the JC Whitney truck catalog or Summit, but I'm pretty sure it was JCW. Anybody out there have any experience with these?
     
  13. Casey 86K5

    Casey 86K5 1/2 ton status

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    I have seen those thermostats before but they were for engine oil coolers. I will look into one of those thermostats for my tranny cooler though. That would keep it up to temp in the winter but still let it stay cool in the summer or when towing.
     
  14. LittlePig

    LittlePig 1/2 ton status

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    I ran the cooler lines for my 72 Cutlass so fluid passed thru the external cooler before going through the radiator cooler. Supposedly, you can run an external cooler and totally bypass the radiator cooler. The two main points of adding a cooler being to get a larger surface area for the cooler and to stop making your cooling system do double duty. A hot rodding article I read recently (and the one I followed) said to run the fluid through an external cooler first, then through the radiator cooler. By doing so, you can "pre-heat" the fluid in the winter, when your external cooler might otherwise cool too much, and in the summer, the internal cooler helps to regulate the fluid temp without scalding your engine coolant (If I recall correctly, tranny fluid can reach 700 degrees)

    Email: xiaozhu@my-deja.com
    ICQ: 84108805
     
  15. Scoobydoo

    Scoobydoo 1/2 ton status

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    If your tranny fluid is 700 degrees forget the cooler cause your tranny is fried already! and probably laying about a mile back on the road (I think you remembered that number wrong [​IMG])

    Just an idea! but you could put some sort of cover in front of the cooler in the winter, to block the air from flowing through it.
    The same principle for why semi trucks cover their whole grill. but I would think you could just cover the cooler?
     
  16. talldogg

    talldogg 1/2 ton status

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    Yeah, and at 700 degrees, make the cover out of Reynolds wrap, throw some steaks over that bad boy and we'll all be over for dinner! I'm sorry I couldn't resist.
    I'll double check the thermostat, if it is for the tranny, I'll post the part number Monday.
     
  17. Scoobydoo

    Scoobydoo 1/2 ton status

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    I think we have just stumbled onto a new way to make beef jerky[​IMG]
    You got the air flow! you got the heat!
    get some aluminum foil, thin sliced beef, salt and teriyaki sauce.
    By the time you get home "JERKY'S DONE!" [​IMG]
     
  18. sosamantx

    sosamantx 1/2 ton status

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    Why don't you just undo one of the lines on the radiator and see if the fluid is coming out of the radiator or the cooler line when you bump or start the motor. You will need 2 people to do this though, as it will come shooting out. Anyway, depending on how big of a transmission cooler that you get/buy/or have, is whether or not you should bypass the cooler in the radiator. The one that I bought for my Nova, said in the instructions, and I was told by my local speed shop not to bypass the radiator cooler, as it was not big enough. Just my 2 cents worth. - Steve

    Steve Sosa a.k.a. "sosaman"
    http://sosaman.home.texas.net/carpics.html
     
  19. dumbfounded

    dumbfounded 1/2 ton status

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    Well here it is transmission fluid life with temp. Your transmission won't last but a few miles longer.

    175 degrees 100,000 miles
    195 degrees 50,000 miles
    212 degrees 25,000 miles
    235 degrees 12,000 miles
    255 degrees 6,250 miles
    275 degrees 3,000 miles
    295 degrees 1,500 miles
    315 degrees 750 miles
    335 degrees 325 miles
    375 degrees 160 miles
    390 degrees 80 miles
    415 degrees <30 minutes

    Temperatures over 350 degrees for extended periods will start to discolor metals inside transmission. This changes the hardness of internal components So all internal stressed components will suffer from fatigue failure under extreme loads even after a normal rebuild.....

    Love, Peace, and Hair Grease...........
     
  20. Casey 86K5

    Casey 86K5 1/2 ton status

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    talldogg-
    I called Summit and they carry a transmission thermostat, but its not listed in the catalog. Its made by Derale and costs about $45. I will be ordering one next week when I get paid.
     

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