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Transmission cooler or not Thread

Discussion in '3rd Gen Tundras (2014-2021)' started by Mad Max, Oct 12, 2020.

  1. Apr 20, 2021 at 5:41 PM
    #631
    Ruggybuggy

    Ruggybuggy New Member

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    186F in Florida? Did you leave the pin in the thermostat?

    I wouldn't worry a bit about 220. I wouldn't start thinking about a cooler until after 240 plus and it would have to happen often.
     
  2. Apr 20, 2021 at 5:52 PM
    #632
    JohnLakeman

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    Toyota's WS fluid is a synthetic blend, not a full synthetic fluid.

    The problem is NOBODY will reveal the temperature limitations of WS fluid. But, we can draw some conclusions based on known limitations of full SYNTHETIC fluids (degradation starts at 280 deg F). Considering that WS fluid and the AB60E/F transmission are unchanged from years prior to 2019 that HAD a thermostatically controlled fluid cooler, my personal conclusion is I would be nervous as hell if my transmission fluid temps were 230 deg F, and really agitated at 240 deg F. At 240 deg F and beyond, I believe you are definitely looking at an accelerated maintenance schedule.

    Monitor your temps and see what you see, but I don't believe a Tundra can tow 3000+ pounds and maintain transmission fluid temps of 230 degs F or less without an auxiliary fluid cooler. The heavier your tow, the higher the fluid temp will be on level terrain. Then if you have hills/mountains, add in the effect of terrain.
     
  3. Apr 20, 2021 at 6:04 PM
    #633
    SSPey

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    Good to know. Especially because I might have undersold the hilly part.

    I’ve driven this a lot, but did just notice via maps that one of the “hills” on my usual tow route is a 2000’ elevation crest (up/down over a steep pass) which I traverse at 35 mph on the curvy side and 55 mph on the straighter side. I will keep an eye on temps and see if they exceed 230/240 when towing begins.
     
  4. Apr 20, 2021 at 6:31 PM
    #634
    marshmellow

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    Got my kit from Nick on Saturday, now I just need to find the time to throw it on.
     
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  5. Apr 20, 2021 at 6:53 PM
    #635
    Kywildman

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    No on the same drive daily prior to the install it literally hit 227* at the same intersection at the same time everday(22 mile trip HEAVY stop and go traffic)
     
  6. Apr 21, 2021 at 7:49 AM
    #636
    Architect

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    Just my 2 cents.. My wife's 2020 Expedition hit 208F, fully loaded with the family and vacation stuff, but no trailer.. We were in stop and go traffic on 95 in about 70f ambient for at least 1hour.. It hit 208F and stayed there until we moved over 30mph. Not sure if Ford put a cooler on it,( I dont care) but we do not have the ford towing package.. We plan on trading it in for the new Sequoia when it comes out..
    On the other hand, I just put Nick's kit in my 2020 Pro this past weekend.. I feel a lot better now about towing and will be keeping the truck as long as possible.
     
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  7. Apr 21, 2021 at 8:46 AM
    #637
    Mad Max

    Mad Max [OP] New Member

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    I wouldnt worry about the oil degrading due to temperature, it is easily replaced. My concern would be the elastomers and soft good in transmission getting hard and brittle.
     
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  8. Apr 21, 2021 at 3:39 PM
    #638
    Jtundra81

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  9. Apr 21, 2021 at 3:41 PM
    #639
    Kywildman

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    And the clutches
     
  10. Apr 21, 2021 at 4:24 PM
    #640
    Mad Max

    Mad Max [OP] New Member

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    That video was painful to watch
     
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  11. Apr 21, 2021 at 4:30 PM
    #641
    Jtundra81

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    Haha , I don’t disagree , the point is that Ford trans are also running hotter
     
  12. Apr 26, 2021 at 10:03 AM
    #642
    SSPey

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    Does the aftermarket cooler work at all when a vehicle is idling, or only when moving? Of course it’d cool best in motion, but does it still cool at idle?

    Last night when towing 3500 lbs on flat ground, my temps w/o the cooler were fine (it was only 55F ambient), but when I stopped for 5 minutes at idle, the pan temps climbed 14 degrees and the torque converter temps were much higher still. I didn’t wait to see how high it’d go, and temps dropped again immediately when moving. But ... I’m curious if the aftermarket cooler would prevent rapid heating after a long tow, then sitting at idle.
     
  13. Apr 26, 2021 at 10:51 AM
    #643
    JohnLakeman

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    An air-to-fluid heat exchanger works primarily by conduction; it requires a large volume of much cooler air to flow past the plates and fins to remove heat from the fluid. If you stop that air flow, then the exchanger's cooling efficiency goes in the dirt. You might have some negligible cooling by convection air currents, but that will be less efficient than that "puck" on the side of the transmission.

    OTOH, if you have an auxiliary cooler, it will removing heat from the transmission fluid as it's generated while driving. The result will be that you won't have a large volume of hot fluid and heat soak in the transmission that will need to be cooled while idling. But, if you have transmission load that generates heat without vehicle speed, as in trying to get unstuck from mud or snow, then there will be minimal cooling from an auxiliary cooler.
     
    Last edited: Apr 26, 2021
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  14. Apr 26, 2021 at 11:14 AM
    #644
    SSPey

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    Thanks John. So if I’m interpret this correctly, it sounds like an aux cooler would lower the baseline operating temp while in motion, but aside from that, it would have minimal direct cooling effect at idle. So if temps are already warm and I expect to idle for more than a couple of minutes, should I just shut everything off to prevent further rise in trans pan temps?

    I’ve noticed that the OBD reader / torque app still displays a temp when the engine is off and the electrical system is on ... and the temp stays high ... and I’m not sure if that is accurate. When I turn on the engine after 5-10 mins of shutoff, the OBD immediately shows a lower pan temp, as if there has been cooling during shutoff (electrical on) that the OBD did not see.
     
  15. Apr 26, 2021 at 11:54 AM
    #645
    JohnLakeman

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    Already warm? Warm as in 215 degrees or less with an auxiliary cooler? :confused:

    I can't offer any advice if you're talking about towing without an auxiliary cooler, except that shutting everything off is counter-intuitive and unlikely to help. Heat stored in the transmission and the fluid is still there. Ways to reduce that heat generation on 2019+ has already been discussed.

    With an auxiliary fluid cooler, your fluid temperature will depend on the the heat exchanger, the load you're towing, and the terrain where you're towing it (and other factors like speed that you control). If the auxiliary exchanger has adequate BTU capacity, I would be surprised to see any fluid temps above 210-215 degrees. If the fluid temperature has been continuously maintained below 215 degrees, then the entire transmission will be at or below that temp. My opinion is you won't see that +14 degrees rise at idle when the transmission hasn't stored a lot of heat in the housing, clutches, gears, etc.

    On any given towing mission, if the transmission fluid temp isn't being held below 215 degrees by an auxiliary cooler, then more heat exchange area (more BTU cooling capacity) is required. The exchangers supplied in the kits, and others that have been discussed here, are about the maximum BTU capacity available in a single fluid cooling exchanger. Experience will determine if it's enough under the worst conditions.
     
    Last edited: Apr 26, 2021
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  16. Apr 26, 2021 at 12:24 PM
    #646
    Terndrerrr

    Terndrerrr it's good to get lost once in a while

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    Is the fan not constantly pulling air through the aux cooler up front, even while idling?

    I would think a steady increase in pan temps while parked idling is from the little hockey puck getting the trans temp up to engine coolant temp. EDIT: but not if you're already at 200ºF. At that point the thermostat would have opened and brought cool fluid back into the transmission and taken more hot fluid out.

    If you have the Toyota thermostat (which I believe at least most of these kits are designed to work with), the aux cooler isn't even a factor until the pan temp hits a bit above 190ºF. The hockey puck will slowly warm the fluid even if you're just sitting there. The two work together to keep the transmission in a specific operating range.

    Mine cools down pretty much immediately once the thermostat opens.
     
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  17. Apr 26, 2021 at 12:24 PM
    #647
    SSPey

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    My situation is that I live at the top of a long hill, restricted to 10 mph (cranky neighbors). So after a long tow, I end with an uphill crawl under load.

    Yesterday I stopped for 5 mins (idle) along the uphill to chat with a neighbor. The pan temp rose quickly from 200 to 214F (the TC hit 225F). I abruptly ended the conversation and kept driving uphill (S1), which lowered pan temps to 206 F until I got home. This was at 55F ambient. I’ll be towing at 95F ambient in a few months, and fully expect a higher baseline operating temp, before the final uphill.

    I can actively manage gearing to keep temps down while driving (including S1 for the final uphill), but I expect challenges ending a hot summer day on that slow uphill grind.
     
  18. Apr 26, 2021 at 12:27 PM
    #648
    Ruggybuggy

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    Are we forgetting the engine fan? When the clutch on the fan kicks in it pulls a good amount of air through the rad and trans ambient cooler. The reason the engine doesn't overheat in stop and go traffic on a hot day.
     
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  19. Apr 26, 2021 at 12:31 PM
    #649
    Ruggybuggy

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    No need to worry about 214F. Don't be overly concerned about TC temps. The TC will run hot at times because of the way it works. Pan temps should be your main concern.
     
  20. Apr 26, 2021 at 12:34 PM
    #650
    Terndrerrr

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    At that point, you're relying solely on the tiny hockey puck to continue to exchange heat between engine coolant (185-195ºF) and the transmission fluid (214-225º or even higher as many are seeing under use that fits within Toyota's towing/payload parameters). There's no way that puck can keep up. There is no other way to cool the transmission if you don't have the aux cooler. Except ambient airflow from cruising under no load.

    If you follow the manual, keeping it in S4 when you tow, you'll prevent a bunch of the extra heat in the TC, but still...

    I wanted mine to run like a 2018, so I installed an aux cooler.
     
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  21. Apr 26, 2021 at 12:36 PM
    #651
    SSPey

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    I’m not worried about the TC per se ... but when the TC is climbing and the pan is also climbing, it gives me an indication of where things are headed overall ... I’ll be doing this same towing routine at much higher summer temps (95 vs 55 F)
     
  22. Apr 26, 2021 at 12:49 PM
    #652
    SSPey

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    Helpful info. Though it was a very cool 55F yesterday, I was pleasantly surprised how tow/haul and S4 worked for towing temps. I did run S3 for some known difficult stretches, to lock the TC in 3rd and prevent gear searching. I’m just trying to explore transmission temp management methods now, before summer heat, so I’ll know more clearly what’s happening when summer rolls around.
     
  23. Apr 26, 2021 at 12:52 PM
    #653
    Ruggybuggy

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    Yes, the TC temps will effect pan temps. I would monitor the temps and see how it does. Keeping it in 4S allows the TC to stay locked up more which results in lower temperatures. You will have to determain what pan temp you will will be comfortable at. Everyone has an opinion. Personally 230 plus is starting to be uncomfortable to me.
     
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  24. Apr 26, 2021 at 1:07 PM
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    JohnLakeman

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    We did forget about the gentle breeze created in front of the condenser by the engine cooling fan. :D
     
  25. Apr 26, 2021 at 1:31 PM
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    JohnLakeman

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    I agree that TC outlet fluid temp will strongly influence pan temperature. In fact, I have attempted to trace the fluid path from the TC through the transmission to confirm that TC outlet fluid is being routed directly to the outlet port and to the auxiliary cooler on pre-2019, but I got lost in those woods pretty quick. It would only make sense because that is the fluid that would seem to have a priority for being cooled.
     
  26. Apr 26, 2021 at 2:43 PM
    #656
    Jtundra81

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    What were you towing and what temps did you see ?
     
  27. Apr 26, 2021 at 3:21 PM
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    SSPey

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    Details are a few posts back. Ambient air 55F, 3500 lb boat, mostly flat with small hills.
    Summer will be much hotter 95F with big hills / mountains, ending in a long 10 mph uphill grind.

    Flat cruising pan was 200F, but rose quickly to 214F at idle (I didn’t let it go higher). 210F on small hills. Again, this was at cool 55F ambient, S4 tow/haul, some S3 (hills), some S1 (10 mph uphill)

    I’m not worried by 200-220F temps, just collecting baseline data now, bracing for summer heat and bigger hills. I want to set a reasonable trigger point now, no mission creep or shifting paranoia. I can’t do the cooler install, so will probably try to identify someone local in advance who can, then simply hit “go” if needed. It has to be swift, I can’t let my transmission temps interfere with fishing.
     
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  28. Apr 26, 2021 at 3:24 PM
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    Jtundra81

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    Yeah I see almost same temps towing my trailer 4000lb . In the summer , I get average 215f on pan
     
  29. Apr 26, 2021 at 3:37 PM
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    Half track

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    So do the pre-2019 Tundra's have the same towing instruction in 4th gear as the newer models?
     
  30. Apr 26, 2021 at 5:04 PM
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    Ruggybuggy

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    Man I wish my wife sucked that hard. :p
     
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