External transmission cooler (again!)
 

Hello Everyone,

I searched for old threads relating to this subject and have found many answers. However, I don't think anyone has ever asked or answered whether a larger cooler was necessary if bypassing the factory radiator cooler. The instructions say to augment the factory radiator/cooler but if bypassing it all together, should a larger cooler be installed? So if a Hayden 678 or TRD cooler (thanks Yotatech to point out that they are the same) is being considered, should a Hayden 679 be used instead since there will be no cooling from the radiator? Lastly, it seems like the most common coolers being used are Hayden and TRD, has anyone tried Derale or Earl's? I am considering using an Earl's 21906ERL since a buddy has one lying around but not sure if might 'over' cool if there is such a thing. Thanks everyone, in advance.

You can over cool your oil, I use a standard size cooler and put two strips of tape across the cooler in the winter, or the oil never gets above 100 degrees. I live in Colorado, I guess it depends on how far north in Nor Cal you are.
I put a temp gauge in before I switched over to know where the temps are at. This way I knew I wouldn't be too cold in the winter.

If you have the option, get one that has a "plate" style rather than the tube style. I run a Derale and have had no issues whatsoever. Take into consideration, where you mount the cooler and how much airflow is available. I have mine run in conjunction with the radiator cooler and a large filter that sits out in front of the radiator as well (helps with the cooling and adds about another quart of trans fluid). My trans temp runs about 150 F under normal driving and around 200 F when towing my boat.

Use one the has a built in bypass if running without the radiator cooler. Hayden/TRD do not. B&M and Tru-Cool do. Do more searching its all been covered here in great detail.

Here is one thread with 17 pages of detail: https://www.yotatech.com/forums/f2/b...cooler-126953/

If that is not enough google this "bypass strawberry Yotatech"

Thanks guys. Okay, I'm looking to get the B&M 70264 (the largest with the 'low pressure drop' bypass feature). Any suggestions on the best place to mount it? I'm thinking about mounting it kind of below the bumper in front of the radiator, basically in front of where the factory/radiator cooler is with the logic that air flow should be the same there as how Toyota wanted it.