Transmission Cooler Lines

I have an auxiliary transmission cooler on my 04 Mustang GT auto. I have rubber hoses and hose clamps right at the point where the stock solid cooler lines attach to the radiator. The rubber lines go to the aftermarket cooler. I measured the temperatures last winter and my transmission fluid would stay under 140* which I feel is way too cold. So I bought this remote oil cooler 180* thermostat from Summit Racing and need to install it. I need more rubber hose and connectors. I don't really know what kind of connectors or hose to ask for at O'Reilly's. What are they called? Just oil cooler line connectors? Is there some common term for them so the auto parts store knows exactly what I mean?


Remote Oil Thermostat with 3/8" NPT(int) Ports

What if I want to fabricate new solid lines to go from the transmission to the thermostat? What kind of solid lines do I ask for? I've seen the bending tool and it seems simple enough to do. What about the connectors? Do I need a flaring tool? I would like to make new solid lines so I don't trash the stock ones.

Any info or feedback would be great. Thanks.

I bypassed my stock cooler.

The PermaCool remote oil thermostat does not have a failure mode that closes both the IN and OUT ports. When cold, the four ports are open to each other. When hot, the two upper ones are isolated from the two lower ones. Even when cold, there will be some flow through the cooler.

As stated, I read all the debates about running the stock cooler in series (before or after) and I don't buy the whole "heating" arguments. If the fluid is at 140* coming out of the auxiliary cooler, it will not pick up any heat from the stock cooler when the outside temperature is around 100*. If you have some data to prove this pre-heating effect, I'd love to see it. Otherwise, I still believe running both coolers in series will result in even more cooling than just one cooler.

Does anyone have info on building solid transmission cooler lines? I want to improve on the rubber lines.

Flghtmstr1 said:

I'm glad the thermostat you bought has a "fail-safe" design.

Running the tranny cooler in series with the original will keep the tranny fluid warm, and for a simple reason. The stock tranny cooler is simply a loop in the radiator, so when your coolant temp is hovering around 195*, guess what's going to happen to your tranny fluid? My best friend's father is a transmission tech working for Chrysler, and he has built many 4R70W / AODE transmissions, including his own (he used to own a '96 GT). He advised me that running the cooler in series was the best way to go, for the reasons I stated.

If you have another viewpoint, or something I haven't considered, let me know. I just want to help make sure your tranny lasts a long time .

As for the solid lines, I'm not sure I've ever heard of someone doing that, so I'm afraid I can't help there. I'm curious though; why do you want solid lines anyway?

Click to expand...

The coolant temp in the radiator does not hover around 195*. The sensor is in the engine block, not the radiator. The coolant in the engine block is what hovers around 195*. The coolant in the radiator is much less. In fact, I remember my dad flushing the radiator in our car when I was a kid (when no one cared about draining radiator fluid in your driveway). He removed the thermostat, had the engine idling, had a garden hose in the radiator fill hole, and the radiator drain plug fully open. The pure tap water coming out of the drain plug was warm. I could put my hand under it and catch water in my palm. Of course actual coolant in a pressurized system will be hotter than that but still not hot enough to effectively add heat to some 140* transmission fluid in a small 18x3 inch section of the radiator.

Really, we're all theorizing here, again. Just like we did in the last umpteen-million threads about how to hook up a cooler. Until someone puts a thermometer between the transmission and the first cooler, between the first and second cooler, and between the second cooler and the transmission, we'll never really know. My uncle's fathers brother's cousin's sister's aunt who is an automotive engineer said so.

I'll tell you what. Right now I have my stock cooler bypassed. If someone can point me to the couplings that will let me attach the rubber hoses to the stock coolelr, I'll run the stock cooler in series and take measurements this winter. If someone has a link to the parts or the part number to Summit Racing parts, I'll perform a test. Anyone?

This has been debated over and over again and this isn't the purpose of this thread.

PS. Solid lines with the proper couplings are more durable and are not prone to decay and rupture like rubber hoses and hose clamps.