Water, transmission fluid, dealer cooler
 

I've got the dealer installed auxiliary trans cooler on my truck, near as I can tell anyway. There is a good look at it in this thread here... https://www.dieseltruckresource.com/...mission+cooler ....looks just like it.

So, the tranny lines are leaking, the fan isn't running, the cooler's radiator is full of crud -- time for a refurbishing. Was going to drop the cooler, disconnect it and clean in up. Pulled the temp sensor off the cooler, then decided to put it back in because I didn't want to mess with the fluid draining out. Left it sitting on the driveway, lines hooked up and everything, theoretically all sealed up -- and blasted it off with the garden hose for a half hour.

Questions I have are -- if I managed to get a small amount of water in there while blasting it under high pressure, how bad is that for the transmission to have a little bit of water in the fluid?

And there was so much crud on the temp sensor, when I put it back in, a little crud might have gotten in the fluid as well. Does the fluid from the cooler get run thru the transmission filter before it makes it into the transmission?

I'm worried about messing up my transmission with any water or crud (very small amounts) that might make it that far. It's the A518 automatic, truck is in my sig. I fret over the transmission on this truck more than anything, don't want to have to get a new one because I'm stupid. Thanks.

you will be fine not enough to hurt anything if its as little as you say

Thanks, I'll try to not worry about it so much.

So the fluid from the cooler would be ran thru the filter in the transmission before entering the valve body etc?

Also, there is an "H" fitting linking the transmission fluid lines that go to the aux. cooler. The "in" line and "out" line look to be bridged together by a metal fitting in the shape of an "H" with horizontal part being some kind of fluid by pass? Hope I'm clear enough. Anyone know what this is? What it does? Thanks.

The H pipe is the cold fluid bypass for the underbed cooler. Cold fluid is rerouted around the cooler and to the heat exchanger on the engine.

Thanks. I'll check into it now that I know what it is called and what it does. It seems that it is a part that would really need to be working correctly.