2006 pathfinder mode door actuator replacement

[marshalwilson]

Hello again, got a silly question for you. I bought an external transmission cooler to replace the possible faulty one inside my radiator....which I don't understand by the way.....but my question is, does it matter if the new cooler is mounted horizontally or vertically? And also, would it be okay to mount it in front of the condenser? Thanks again.

[smj999smj]

What don't you understand about the cooler inside the radiator?

Anyway, you don't need to an an external trans cooler. There is already one installed from the factory that does a great job at that; you only need to re-route the transmission cooler hoses. If you do towing and really want the protection of the extra cooling, you would be better off getting your money back for the trans cooler you purchased and investing it in a new radiator. Aftermarket radiators don't cost much more than a quality, aftermarket trans cooler.

[marshalwilson]

I think I'm more confused than I thought I was. I'm obviously missing something here. The transmission fluid is routed through a tube system inside the screaming hot radiator to "cool" it?? ...and my pathfinder already has an external transmission "air cooled" cooler?? Is the cooler looking thing about 12 inches square in front of the radiator part of the a/c system or is it an external transmission cooler?

[smj999smj]

Well, "screaming hot" is subjective. Transmission fluid's ideal operating range is 175-200 degrees F. Your engine's thermostat is probably rated at or about 180-195 degrees F. So, the temperature of the engine coolant in the radiator is perfect for maintaining the temperature of the transmission fluid, which is one of the reasons the "cooler" is mounted inside the radiator. This also helps get the transmission fluid up to "normal operating temperature" quicker. Liquid-to-liquid coolers are also far more efficient than air-to-liquid coolers. Perhaps the word "cooler" can be a bit confusing because it probably does more warming of the fluid than it does cool it, but, if the temperatures were to enter the radiator's integral cooler at an abnormally high temperature, it would actually cool down the fluid.
The way the system is designed is that the transmission fluid first enters the auxiliary cooler mounted in front of the A/C condenser (yes, that 12" cooler looking thing) which does most of the actual "cooling." Then, the fluid travels to the cooler inside the lower tank of the radiator. If the trans fluid is hotter than the engine coolant surrounding the cooler, then the trans fluid will get cooler, which usually isn't the case. In most cases, the trans fluid is usually around 150-160 degrees F. when it exits the auxiliary cooler, so when it enters the radiator's integral cooler, it will likely be warmed slightly to the temperature of the engine coolant surrounding the cooler, before returning back to the trans. So, maybe the word "cooler" isn't the best name for it, but it's a lot simpler to say than "radiator integral transmission fluid temperature maintainer!"

[marshalwilson]

You explained that whole thing incredibly well, thank you. I very much appreciate you taking the time to educate me on this whole thing, the internal "cooler" thing really threw me, but it all makes perfect sense now.