Transmission Cooler installation

[gandalf]

I'm gearing up to install the transmission cooler I recently bought. It's a Tru-Cool Max. It should hold the temps down nicely. In the process I'm going to change the fluid, of course, change out the filter, and change over to a deeper pan with a drain plug.

Here's the question, though, and I very vaguely recall its being discussed before, probably on TDS. The cooler arrived complete with hose for the hook-up, and brass hosebarbs. It's marked as 23/64". The hose on the truck is marked as 3/8". That's 1/64" difference. At some point I'm going to have to interface these-- put a 23/64" hose onto a 3/8" nipple, and maybe a 3/8" hose onto a 23/64" nipple. This should work, shouldn't it? Just grease up the barbs and slide it on in? Its the slightly larger hose going onto the slightly smaller nipple which has me worried. Any way to insure a good seal on that?

TIA for any help or suggestions.

 

[Mr_Roboto]

I'd say it's more a case of "fancy measuring" than anything else, they will work fine. I always use 2 hose clamps at each connector, use fuel injection clamps if you can find them, they won't dig into the rubber like regular worm gear clamps do.

Remember to install the cooler AFTER the in-radiator cooler. Otherwise the radiator just heats the fluid back up. If you don't know already, the return line is the one that goes to the rear of the transmission.

 

[towcat]

Remember to install the cooler AFTER the in-radiator cooler. Otherwise the radiator just heats the fluid back up. If you don't know already, the return line is the one that goes to the rear of the transmission.

ATF needs to be around 200deg to be working properly. in the parts of kali that doesn't see snow, its ok to run the cooler after the radiator. Parts of the country that see snow or multiple days of freezing temps should be running the cooler before the radiator.

 

[h2odrx]

can i just run the cooler alone? not use the radiator?

 

[gandalf]

can i just run the cooler alone? not use the radiator?

It's my understanding that running through the radiator serves a dual purpose. It helps cool the fluid once the transmission heats it up, but it also helps to heat the transmission fluid to a normal operating temperature when the vehicle is first started. The transmission wants it's fluid within a certain temperature range for most efficient operation.

 

[Mr_Roboto]

Remember that the cooler is in the bottom of the radiator. The radiator doesn't even START to get warm until the engine has warmed up enough for the thermostat to open. And the bottom of the radiator is the "out" side, where the already cooled coolant is.

At least some years of the E4OD / 4R100 have a thermostatic bypass, so that they do not send fluid to the cooler until the transmission is at operating temperature.

Quote: "can i just run the cooler alone? not use the radiator?"

No. The fluid to fluid cooler is much more efficient than the air to fluid cooler. If you used just the air to fluid cooler, it would have to be much larger to compensate.

 

[sle2115]

I have always ran mine after the radiator as suggested and we see freezing temps. I have never ran my trans fluid at 200 degrees either though! So I must be missing something. I can say, my last three vehicles were sold with over 300,000 on the automatic transmissions and still running with nothing but fluid and filter changes about every 50,000 and running temps of around 170-180 degrees hot, but most of the time less. So if you have less than 200, personally, I wouldn't worry about it and in most cases, I always tried to get it as low as possible. My last fullsize truck, 350 Chevy/TH700 never ran over 160 unless I was pulling something!

Also, I would not use any lube on the fittings. If they go on too easy, they can come off to easy. If you were to measure the 3/8 rubber line, it will measure smaller than that as well, 1/64 isn't going to matter, but a good snug dry fit is best in my opinion rather than a well lubed one. A mechanic I worked with one day started insisting that we put av-glue on all radiator hose fittings. In one month, we had removed about every one that went out that way because as the temp rose, the av-glue got gooey an let the hoses slip around and leak. Talk about fun, you ever try to clean av-glue off your hands, try it on upper and lower radiator hose fittings on some of these front wheel drive cars that you can't even see!

Just my .02 worth!