Did I hook up my trans cooler wrong?
- Thread starter sbelyo
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propellerhead
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Do you have some data to support this? I'd like to see.
I had my aux cooler hooked up standalone. I bypassed the stock cooler. Before the mod, my Transmission Fluid Temperature (TFT) according to my Xcal2 would hover between 180* and 200*. After the mod, it would hover around 130*. I felt it was over cooled so I included the stock cooler in the loop. The fluid now goes from the transmission to the aux cooler to the stock cooler and back to the transmission. The theory everyone seems to talk about is that the stock cooler will warm up the fluid.
Bull****.
It didn't make a difference. Until the engine gets to 180*, the thermostat is still closed. With the thermostat closed, the coolant in the radiator is cold. Even with the thermostat open the radiator is bleeding off a lot of the heat into the airstream. I'm pumping 130* transmission fluid through a small section of the radiator. There's not enough temperature difference to make a difference.
Cool your guns there son. Sorry I didn't do a in depth study on this. I don't think its too difficult to figure out though, passing a cooler liquid next to a warmer one, some heat transfer will occur once the engine is up to temp. I didn't say it was gonna boil it.
I don't even run a extra cooler on my car because its not needed in my case but Ive been told and have read that the aux. cooler should be inline after the factory cooler. Have a nice day.
Ok, I understand what you are saying but I have had my B&M cooler after the stock cooler for 80K miles without issue. Yea my trans temps get stupid low sometimes but that is alright with me.
propellerhead
New Member
I'm not your son, little boy.
If the fluid never warms up to operating temp, I don't think we would see any issues. It's just less efficient. I suppose it's like driving with a thermostat stuck open. More wear and tear. Even with my stock cooler in series, I have to do some hard driving to see 150* TFT. I had my Xcal connected at an autocross even and did my 4 laps in 2nd gear. My TFT got up to 170*.
simple answer
You want fluid coming from the tranny to go in the _top_. You want return to the tranny to come from the bottom. Why? Simple physics. As the fluid is cooled by running by the radiator coolant, cooler fluid sinks to the bottom to be returned to the tranny, the hot fluid stays at the top until it cools and drops. If you hook it up backward, the hot fluid goes in at the bottom, quickly rises to the top and returns to the tranny, without being cooled as much as normal, so it is less efficient and the fluid temp rises...
that's all there is to it, and that is assuming your radiator actually has a fluid reservoir inside, rather than just having small lines running thru the aluminum fins like the aftermarket add-on coolers. For them, there is no good in/out preference, the fluid just passes thru dumping heat to the fins along the way...
You want fluid coming from the tranny to go in the _top_. You want return to the tranny to come from the bottom. Why? Simple physics. As the fluid is cooled by running by the radiator coolant, cooler fluid sinks to the bottom to be returned to the tranny, the hot fluid stays at the top until it cools and drops. If you hook it up backward, the hot fluid goes in at the bottom, quickly rises to the top and returns to the tranny, without being cooled as much as normal, so it is less efficient and the fluid temp rises...
that's all there is to it, and that is assuming your radiator actually has a fluid reservoir inside, rather than just having small lines running thru the aluminum fins like the aftermarket add-on coolers. For them, there is no good in/out preference, the fluid just passes thru dumping heat to the fins along the way...
There are significant differences between a transmission and engine. 130 deg fluid is much better than 170 deg fluid for keeping a transmission running a long time under severe duty. I have seen industrial applications where we pumped chilled water through heat exchangers in the transmissions to keep them running for years.
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