Auto trans cooler pipe

[CFI]

Can someone explain how the auto trans cooler pipe works? In the parts diagrams I see two rubber trans cooling lines with metal ends that connect to either end of a coolant pipe. Does that coolant pipe have a separate passage inside for the transmission fluid?

[Ron]

You got it right... The coolant pipe has a tank/chamber inside it which connects to the two small ports. The transmission pumps its fluid through one port and out the other. This allows the coolant running through the two large ports to warm/cool the trans fluid.

[CFI]

You got it right... The coolant pipe has a tank/chamber inside it which connects to the two small ports. The transmission pumps its fluid through one port and out the other. This allows the coolant running through the two large ports to warm/cool the trans fluid.

Thank you

[David T]

A few things about the cooler and the automatic transmission;
PJ Grady sells a heat exchanger that wraps onto the cooler to help cool the oil. He also sells a shield for the exhaust cross/over pipe to keep the transmission cool
Make sure the two hoses from the transmission are not leaking or cracked, if they are, they should be replaced
Check the fluid level as per the procedure in the Workshop Manual. Also make sure it is not burnt smelling or dark or gritty.
Don't forget there is also a fluid level in the final drive that must be checked.
If the shift computer is not shifting properly get it fixed ASAP before it causes internal damage to the trans.
Make sure the vacuum hoses and pipe going to the vacuum modulator are connected and not leaking.
Make sure the wiring harness to the shift computer is secured away from the hot exhaust pipes.

[Jonathan]

Can someone explain how the auto trans cooler pipe works? In the parts diagrams I see two rubber trans cooling lines with metal ends that connect to either end of a coolant pipe. Does that coolant pipe have a separate passage inside for the transmission fluid?

It's basically just a simple heat exchanger. Two separate fluids flowing by each other, with the hotter one heating the cooler one (i.e. the cooler one taking some of the heat away from the hotter one). The fluids do not mix as they transfer heat across the metal that is between them. You can think of it as a 'tube and shell' heat exchanger, although I suspect there is only one tube in there (I've never taken one apart). The small hoses with metal ends contain the ATF (auto trans fluid) and the larger diameter 'pipe' is connected to the engine coolant system.

Here's a quick video of one. Again, the one on ours cars probably has a lot less inner tubes and no baffle plates.


https://www.youtube.com/watch?v=mw7J8zyLsvg

[CFI]

Good stuff guys, thank you

[cis6409]

Does that same pipe also have 2 different size ends on it?
One hose diameter is not the same as the rest of the coolant pipe work, Iirc??

Shane

[David T]

Does that same pipe also have 2 different size ends on it?
One hose diameter is not the same as the rest of the coolant pipe work, Iirc??

Shane

The cooler has the same size on both ends but what you are referring to is the curved hose from the long coolant pipe underneath to the trans cooler. The pipe is a smaller size than the cooler so if you don't get the "special" hose from a "D" vendor, and instead try to use an ordinary hose which is the same size on both ends, it is very difficult to get it to fit onto the oil cooler. Wetting the inside of the hose with anti-freeze can help slip it on.

[Jonathan]

Does that same pipe also have 2 different size ends on it?
One hose diameter is not the same as the rest of the coolant pipe work, Iirc??

Shane

This is the rubber hose with the two different sized ends you were thinking of:

http://store.delorean.com/p-10608-hose-connector.aspx

[cis6409]

That's what I was thinking about, cool, thanks guys for clearing that up :cheers:

Shane