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Transmission cooling fan with thermostat - where to mount?


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I would like to add a thermostat controlled fan to cool the transmission fluid.  When I looked at the transmission cooler mounted at the very front of the vehicle I didn't see any room to mount a small fan dedicated to the transmission cooling unit.  There isn't much room between the transmission cooler and the front plastic grille. Overall there is a stack of the small transmission cooler in front (like 10" cooler), then the cooler for the AC system that is the same size as the radiator, and then the engine radiator behind that.  Last in line is the clutch driven fan with shroud.   Is there some trick to adding a fan in the very front on the small-ish transmission cooler?  Or do I need to behind an entirely new transmission cooler somewhere else and use a thermostat driven fan controller to turn it on and off?  

The problem I am seeing is that when I climb the engine doesn't get overly hot and so the clutch driven fan doesn't run all that much, but meanwhile the transmission fluid get hot and I don't have a way to cool it on demand.  On the freeway I generally see about 165 to 170 F for fluid measured coming out of the trans just before it enters the bottom of the main radiator.  It gets up to 200 F sometimes when really stressed and I'd like to  keep it lower than that.  

I was not able to find any other previous discussion on this particular topic, but please point me in the right direction if I searched poorly.

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Those temps are fine measure it at the cool side and see what you get that is the temperature the transmission uses to do its job. Mind you it is coolant temp that cools the trans fluid that's why  the cooler is located at the bottom of the radiator. The trans is bolted to the engine the engine runs at 180* so that is pretty much normal temps you are seeing. 

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20 minutes ago, Maineah said:

pretty much normal temps you are seeing

Good to know that you don't think I'm running too hot.  Are the spikes to 200 for short periods on the fluid coming out of the trans acceptable?    I get anxious going up a hill with the engine running cool but trans temps climbing rapidly.   I can chill (pun intended) if indeed I'm just operating within an acceptable temperature range.

Perhaps I should just keep things as-is and keep an eye on my trans fluid color.  No need to add some complex cooling system if I'm not actually having a serious heating problem.  I've been systematically changing it out 2 quarts at a time for the last 8 months.  I think I'm on fluid swap #5.  I've also just received a filter and pan gasket so I plan to take a look inside and see how things look when I change the trans filter.   

I know there is a lot of debate about where to measure the trans temp.  I put mine in an easy spot.  Some data is better than no data, I guess.  Likely I could get a better idea of what is going back into the trans by moving the sensor to the other side of the radiator as you suggest and catching what comes out of the trans cooler.  It may be relatively simple to move that sensor over to the other side.

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If you're going to be using a temp sensor controlled fan for your trannie cooler, you can mount it horizontally.

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I think I'll just leave it as-is or maybe move the sensor.  It doesn't sounds like I'm cooking the fluid too much.  If I do want to add any extra cooling in the future I'd likely just add a separate remote cooler with a thermostat controlled fan.  For now it's fine as is.  Thanks for the comments.

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1 hour ago, AtlantaCamper said:

I think I'll just leave it as-is or maybe move the sensor.  It doesn't sounds like I'm cooking the fluid too much.  If I do want to add any extra cooling in the future I'd likely just add a separate remote cooler with a thermostat controlled fan.  For now it's fine as is.  Thanks for the comments.

Bottom line if it ain't broke don't fix it! Tras heat is produced by converter slip it not actually the moving parts that cause the heat. To reduce the heating use OD spairlingy only on flat ground many people don't use OD at all. From what you are seeing there is zero issues with the trans cooling system if you really want more cooling I would not get involved with any thing complex like extra fans that's just something else going somewhere to break your best beat would be a real axillary cooler stuck in front of the radiator and skip the dinky little Toyota bolt on, Hyden makes all kinds of transmission coolers most are universal fit. You can leave the sensor where it is that is as good a place an any that will give you an ideal just how hard the trans is working you all ready know once it's been through the coolers it's going to be cooler. 

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6 hours ago, Maineah said:

if it ain't broke don't fix it!

I agree.   I had the incorrect assumption that the fluid was getting too hot.   

6 hours ago, Maineah said:

use OD sparingly only on flat ground many people don't use OD at all.

I used OD very little on my trip last week.   Unless there is a downhill run or a tailwind the OD caused the trans temp to go from ~165 to 185 in pretty short order.  I pretty much leave it off and run high RPMs in 3rd.

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