Transmission Cooler

[Gary Allan]

Counter current is a viable flow path. You're at the max differential where the fluid sees the coolant first. I guess it's not actually counter current since it's a crossflow rad ..but it's counter flow to what we consider convection current. I'm unsure how much different the top vs. bottom temp is there. Except for convection differences, just turn it on it's side and it would make a little more sense.

 

[Gary Allan]

Originally Posted By: onion
I can't say about other OEM applications, but I know that some GMC medium-duty trucks (school buses, etc.) use a cooler in the radiator and an external oil-to-air cooler in series. In these applications, the atf goes through the oil-to-air cooler first, then through the cooler in the radiator. And IMO, that's the preferred way to route these setups, though I'm definitely in the minority around here.

My reasoning is this: Maximum heat transfer will occur at maximum temperature differential. Therefore you will get the MOST out of your oil-to-air cooler by running the hot atf through that cooler first. This will get rid of a significant heat load before it is transferred into your engine's cooling system... so this improves overall cooling system efficiency. Plus, by running the atf through the oil-to-water cooler before returning to the transmission, you'll avoid over-cooling in the winter.



I lean this way too. No one else seems to find merit in it, but they're looking at it from MAX fluid cooling. I don't necessarily need for or care about getting the coldest fluid. I just need to shave the peaks that are out of control. I'm also unsure of how true the assertion that you're getting the most efficiency in cooling installing it post rad. I doubt you reach equilibrium passing through the rad cooler. No one really knows what temp the coolest part of the rad is at any given time. That is, the assumption that it will be hotter ...too hot ..more hot than you think is proper ... is just speculation.

If I incorporate a thermostat on mine, I'll cycle the auxiliary in and out before the rad cooler. There it will only work in temps in excess of 180F.

Shaving the peaks.

 

[mechtech2]

A good thermostat system would be ideal. But what a pain!

For 10 seconds and no cost, use a piece of cardboard over the fins of the aftermarket cooler when it's really cold.

To seal cut metal lines that you are going to attach rubber lines to, use two clamps on each end, 180 degrees rotated. You can also SLIGHTLY flare the tube ends where they were cut. Smooth any sharp edges in any case before assembly. Give enough line to let the engine move and rock.