2010 Explorer EB 4x2 4.0L Transmission Fluid Change

[Littleant]

Havfun Tech By Trade is 100% correct nothing to add to what he said. Pan looks real good. Dealer was correct about the flush. The way you did it is just fine. Nice job.

 

[Havfun]

That's how its supposed to work. The system is fully pressurized, and when you cut the line the fluid will flow from both directions. The difference is there is less pressure coming from one side, and it circulates against the lower pressure....

Thanks Tech and Littleant. That sort of makes sense and doesn’t. You are right that one side had more pressure than the other and its easy to see that circulation will be in the direction of the higher-pressure side. Here’s what makes no sense to me:
First, the lower pressure side was the side leading to what should be the output side of the radiator (passenger side of radiator). That means the flow of fluid is really into the passenger side (lower pressure) of the radiator and back to the transmission after exiting the driver side of the radiator. But the driver side of the radiator leads to the lower port on the transmission which is the output port, not the return port! This means flow direction is opposite to what I expect it to be, that is opposite to the arrows in this picture: Transmission Cooler lines. It also means that fluid flows from the transmission first to the auxiliary cooler and then to the radiator cooler. This also would be an unconventional way to plumb in the auxiliary cooler based on all I’ve seen on this. Very confusing at least to me it is.
Second, I’ve used this same method on my ’97 Thunderbird and my Toyota Camry. In both cases the flow direction was as expected and nothing came out of the other side of the broken line!

So, I guess I’m still kind of confused and can’t quite make sense out of this.

 

[Littleant]

HavFun. There is no suction line just pressure out. If you were to remove both lines at the trans fluid would run out of both ports on the trans but one would have more pressure (pump presure) that would overcome the other. As Tech By Trade said the system is fully pressurized. So let's say you cut the line leaving the aux cooler going back to the trans fluid would run out of both ends of the line but there would be more pressure on the aux cooler end then the trans end even though they are the same line.The pump pressure overcomes the lower presure. Hope it helps.

 

[Havfun]

Thanks for all of the help folks! The transmission is also very happy with the all new Mercon V and filter!

 

[Littleant]

You are welcome Sir. I like it when things turn out right