Transmission Cooler Write-up

[Kryptoroxx]

After doing some reading the 4th gens have the same trans cooler running through the radiator and in the v8 models there is an external aux cooler on the right side of the condenser in the front. My plan is to reduce the ability of the dreaded pink milkshake by running a larger transmission cooler and eliminating the radiator cooling section.

The theory behind the parts I went with is that with a bypass installed the at fluid will only be running through the cooler at greater than 170 degrees.

I'll add links later but I went with a true cool system in which the cooler itself has a semi bypass system built in as well where thicker fluid only runs through part of the cooler and thinner fluid runs through the entirety of the cooler.

The bypass will be in line before the cooler and act in a capacity to assist warm up in cooler environments and once open allows flow through the larger cooler.

I will be removing the standard stock aux transmission cooler in order to make room for the new trans cooler so I am not blocking more of the condenser than necessary.

I had a thought of cleaning the stock cooler out and running the actual engine oil through this as a secondary cooler but I've never had an issue with the stock coolant cooler keeping up with engine Temps.

I should have the parts here by early July and begin install then. I'm still working on multiple projects but this should be a one day install.

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[Kryptoroxx]

On a side note I was able to find a champion all aluminum radiator for the tundra that is the same size as the 4runner. I am going to do some more research on this as the recommended time for radiator replacement is 100k. I happen to beyond that mark by 60k so that might be another project to be done before winter. I wouldn't expect to be replacing this radiator unless failure is expected or the new coolant doesn't mix with aluminum radiators. I would expect that it is compatible with the new Toyota long life coolant.

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[4x4mike]

I had a thought of cleaning the stock cooler out and running the actual engine oil through this as a secondary cooler but I've never had an issue with the stock coolant cooler keeping up with engine Temps.

Do you mean that you'd keep the stock transmission cooler and run oil through it? Where is the primary cooler if this would be a secondary cooler?


And when you say you haven't had an issue with the stock cooler keeping up with engine temps do you mean when the engine temps are high the tranny temps are fine? With the stock tranny cooler.

[4x4mike]

I'm the second owner of my V8 4th gen and it's got a Hayden cooler inline with the stock cooler. Lines from the coolers go back into the passenger side of the radiator. I have an Ultra Gauge but it doesn't give me tranny temps. I've always assumed they were in check.

I'd rather not dig into something that already works, and has already been dug into, but I wonder if I'm getting any benefit from what I have? The AT fluid still runs through the radiator which I guess is okay. It makes me feel better I haven't seen any pink milkshake issues in 4th gens like the 3rd gen see.

You mentioned an oil cooler. Do you have one on your 4Runner?

**EDIT** I have no idea why the uploader loads the picture upside down.

[Kryptoroxx]

There is an engine oil cooler but it is located at the filter. It's a coolant powered device and I would imagine that it does a pretty good job of keeping the oil at 190 or so. I never had any high Temps even when I was towing 6500. I also don't know enough about what it would take to relocate the filter and introduce a cooling system that would beat the stock cooler.

Trans setup looks just about what mine will look like. Still kind of formulating what the whole system will look like but I think the way it will end up is when the at fluid is too cool it will only run through the smaller stock cooler and when it's hot it will run through the larger one. For now I will run the stock coolant as well till I can replace it with an all aluminum radiator and get rid of the possibility of a pinko disaster.

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[Kryptoroxx]

Shoot I would have thought the mail would have gotten here sooner. Small changes. I'm going to mount a aluminum radiator in the springtime but for all intensive purposes the radiator will stay in the circuit. I just can't help but think liquid temp regulation is better than air cooling. Porsche would disagree I'm sure.

So the bypass will be connected to the stock mini cooler and the high temp circuit will be routed through both the new cooler and the mini cooler. That should help with the increased Temps while towing and assist with keeping an operating temp during all other driving conditions.

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[Kryptoroxx]

Everything has arrived. The bypass is quite a bit smaller than I expected. Now that I've finished up staining the deck for the holiday I can begin work on the transmission next week without fear of ignoring the house.

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[Kryptoroxx]

Everything has arrived. The bypass is quite a bit smaller than I expected. Now that I've finished up staining the deck for the holiday I can begin work on the transmission next week without fear of ignoring the house.

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I spoke too soon. The army needed its two weeks. Right now the heat index is sky high here so this might be shelved till I can get to it.

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[4x4mike]

I didn't realize you were still in. Have fun.

Amazing the weather you have. Frozen cold to really hot.

[Kryptoroxx]

I didn't realize you were still in. Have fun.

Amazing the weather you have. Frozen cold to really hot.

Retirement comes in a few years. Weather hasn't been terrible but I was wishing in the middle of this op that I could do the insulation in my attic lol. It will get done though. I'll keep busy for the entire summer.

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