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Technical Trans Cooler Sizing

Discussion in 'The Hokey Ass Message Board' started by Flat Six Fix, Jun 27, 2021.

  1. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Hey all, been using this external trans cooler in 55 Fargo.
    It's a stock 1986 318, 904 trans.
    No trailer pulling going on.
    Is this cooler big enough?
    To date not much issue.
    Thanx 20210627_082905.jpg 20210627_082850.jpg 20210627_082905.jpg
     
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  2. squirrel
    Joined: Sep 23, 2004
    Posts: 49,794

    squirrel
    Member

    should be big enough. But it would help to have it where air will flow through it....like in front of the radiator.

    If the transmission fluid does not get yuckky, maybe it's doing a good enough job. Discoloring, or getting a burned smell, are symptoms of overheating.
     
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  3. canman
    Joined: May 6, 2010
    Posts: 122

    canman
    Member

    What is the fluid temp. ? If it's around 180-200 degrees it's fine. If not it needs something different, bigger cooler, more airflow. I just fixed a Pantera cooling system by replacing the factory fans with Spal pushers 230 to 190 degrees. Air flow is important
     
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  4. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    9
    Jim, big hole open beside rad lots of airflow
     

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  5. oldiron 440
    Joined: Dec 12, 2018
    Posts: 2,399

    oldiron 440
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    Do you still have the transmission cooler in the radiator?
     
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  6. squirrel
    Joined: Sep 23, 2004
    Posts: 49,794

    squirrel
    Member

    as long as you're moving.

    If it's not cooking the fluid, it should be fine.
     
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  7. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
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    Just back from a drive, 80 outside trans cooler was 158
     
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  8. nosford
    Joined: Feb 7, 2011
    Posts: 550

    nosford
    Member

    I think you just answered your own question, it's big enough to achieve that low of temp on an 80 degree day then the transmission is happy. Sometimes the trans will get hotter during a stop and go stuck in traffic drive as the airflow becomes an issue as the torque converter has to slip a lot. That is where the most heat is generated is in the torque converter.
     
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  9. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    I agree, 90% of my driving is rural, in flat country...
     
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  10. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
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    .
    Nope, never did...
     
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  11. Ice man
    Joined: Mar 12, 2008
    Posts: 984

    Ice man
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    My profession is HVAC and Ice machines. When building my truck, heat was a concern as its hot most of the time in the Virgin Islands. and the tranny was an AOD Ford, so cooling was a major concern and getting a good unit was a problem cause shipping to the Islands is the pits. So I found an old refrigeration condenser in good condition and nestled it in front of the oil pan and added a S/S scoop, to catch as much air as possible. Worked better then I could have imagined, and was very cheep and easy to hook up. We are Hot Rodders, we make things, were not all full of money, and we can do it. Iceman
     
  12. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,932

    Blues4U
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    from So Cal

    That's a good oil cooler, plenty of capacity in that one. First off, it's the better plate/fin design, better than the tube & fin, much more capacity. And it's about 18 rows if I counted correctly, by what, looks like about 12", that's a pretty good size cooler. The big heat generator in an auto trans is the torque convertor, if it's a stock(ish) stall speed I'd day you're good to go. The only problem may be if the stall speed is equal to or above your highway speed rpm, that's when you'll have troubles.
     
  13. oldiron 440
    Joined: Dec 12, 2018
    Posts: 2,399

    oldiron 440
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    I like that type of cooler also, I know Ford has used it. I would try to get as much airflow as possible. If you don't have a gage or even if you do keep an eye on the fluid condition. I suspect you will know fairly quickly if it works.
     
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  14. 51504bat
    Joined: May 22, 2010
    Posts: 3,015

    51504bat
    ALLIANCE MEMBER

    This a Ford factory cooler for a super duty. Looks as though yours should be fine for your application. But as others have said, as long as it gets air flow. 00Z0Z_6JTiw0QckgFz_0CI0lM_600x450.jpg
     
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  15. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
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    Yes, it's a stock A999, or modern 904 with lockup torque converter.
    Drove it like this for about 1500 miles so far.
    Summer and vicious heat is short lived up here, think just north of Fargo ND...
     
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  16. I agree stacked plate coolers are the most efficient. I ran 2 that size in my old ‘54 Ford panel with a C6, it had a temp gauge and would rarely reach 100-115 deg. I have a single one on my ‘41 Ford p/u with an aluminum powerglide and it keeps it cool also, I should mention that BOTH trucks did not have a radiator cooler.....only the external coolers.
     
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  17. Mr48chev
    Joined: Dec 28, 2007
    Posts: 30,027

    Mr48chev
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    That big hole that shouldn't be there means that when you are going down the road air is taking the path of least resistance and bypassing the radiator.. Put the panels that belong there back and put the cooler in front of the radiator where it belongs so the fan will pull air though it at low speeds and the panels will direct air to the radiator on the road. That will save you coming back after the first road run and asking why your car overheats on the highway.
     
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  18. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
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    Not sure where you got this idea?
    And yes that hole is factory not cut out.
    My rad is got great open airflow too.
    But your hypothesis is dead wrong.
    Truck never runs too hot highway or around town.
    Actually runs at nice 185 never hard to start on hot days either....
     
  19. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 5,067

    57JoeFoMoPar
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    I honestly don't think you have an issue.
     
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  20. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
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    Yes agree, but never hurts to ask...or does it...lol
     
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  21. justpassinthru
    Joined: Jul 23, 2010
    Posts: 338

    justpassinthru
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    I have been building automatics for over 40 years and will say your rebuilder is full of poppycock.

    In a 2004R, the fluid doesn't flow any slower in OD range than in 3rd or D range.
    Will the fluid run cooler, maybe but nominal. The other wear generated by doing so, does not offset possibly running a little cooler as being a benefit.

    Reasons to drive in D range in some vehicles was mostly to prevent chug a lugging due to OD shifting in too early in MPH. My off topic Grand National is one of them. Under light throttle, it will shift into OD at around 40MPH. That engine/ diff gear ratio does not like lower RPM's and will chug a lug at those speeds.

    The only difference between D and OD range is in D, the overrun clutches are applied, which gives coasting downshift engine braking and OD shift is locked out. The amount of fluid flow is the same.

    Also every time the clutches are applied, there is some sort of wear generated. So in my opinion, shifting to neutral when stopped generates more wear, than leaving in gear.

    Think about a manual trans clutch. Every time the clutch is engaged and disengaged there is wear generated. Automatic friction clutches are no different.

    Bill
     
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  22. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Hey all took truck into town to fuel her up. 15 mile round trip.
    Outdoor ambient temp near 90.
    Truck ran in Normal temp range 185 or so.
    Trans cooler around 150 or so.
    So not bad, but no mountains or hours of driving either.
     

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    Last edited: Jun 30, 2021
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  23. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,932

    Blues4U
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    from So Cal

    I have to say my bullshit detector was going off too...
    I'm with you here as well. I don't think there is any benefit to the transmission at all to shift it into neutral at a stop. Besides wear to the clutches as you put it back into gear, there has to be some wear to the entire driveline as it is unloaded and then loaded back up again, repeatedly, at every stop.
    It was also to prevent the transmission from hunting between D & OD
     
  24. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
    Member

    Thanx Bill, with respect to my current trans a 904 or 999 with lockup torque converter.
    Does this work somewhat like an OD with respect to dropping RPM a bit and better fuel economy,?
    Thanx
     
  25. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 8,922

    mgtstumpy
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  26. Flat Six Fix likes this.
  27. Flat Six Fix
    Joined: Feb 6, 2010
    Posts: 1,271

    Flat Six Fix
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  28. blue 49
    Joined: Dec 24, 2006
    Posts: 1,438

    blue 49
    Member
    from Iowa

    It seems to me that way back when, I took a hydraulics class for my job and the instructor told us hydraulic fluid could be too cool. Seems like he recommended 180-200*. That was a long time ago and I may be wrong. DSCF2767.JPG
    I have this tube & fin 2 pass that is sold as a frame rail cooler, so it should work in front of the radiator just fine. It has for about 10K miles so far anyway.

    Gary
     
  29. justpassinthru
    Joined: Jul 23, 2010
    Posts: 338

    justpassinthru
    Member

    Most stock stall speed torque non lockup converters back in the day, were in layman's terms, about 9/10 efficient. Meaning there was always about 1/10 slippage in the converter.

    Some higher stall speed performance non lockup converters are even higher in the slippage at stall speed, depending how the converter was made, therefore even further less efficient.

    The lock up feature removed that slippage. That may not sound like much, but that could relate to just about 200 RPM lower at highway speeds, depending on the vehicle.

    Bill
     
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  30. justpassinthru
    Joined: Jul 23, 2010
    Posts: 338

    justpassinthru
    Member

    Are you sure the trans is a lockup version?
    Earlier Lockup 904 style trans has hydraulic controlled lockup and the real late ones have electric controlled lockup, with a electrical connector sticking up out of the case.

    Most hydraulic controlled lockups applied lockup at too low of road speed. We would replace the spring on the lockup control valve to a stronger one to raise the lockup speed.

    The only way to verify an earlier unit, if it is a lockup model , was to look at the input shaft. The spines on the input shaft did not go all the way to the end. There is a machined surface at the end of the shaft. You could probably also ID the trans with the model numbers, if original.

    Bill
     

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