I got mine from Jegs. Because I was putting an aftermarket trans cooler in the system, I had no way of knowing if it is sized right. Too hot or too cold is a bad thing. So I installed this thermostatic valve in the line that does not open until the trans reaches 180 degrees. This is a few degrees higher than the FSM specifies, but close enough for my intuition here.

http://www.jegs.com/i/Derale/259/13011/ ... oreDetails

The one I purchased came with a temp gauge,which is nice. Without this one would not know if it was in fact working as designed. I hate to be so cynical, but it is almost certainly made in China, and I have rather poor experience, and expectations from the aftermarket speed parts made in China. In the driving I have done so far, it has moved right up to 180 and stayed there. We will see how it does in the hot weather.

It is a rather clever design. It does not simply cut off the cooler 100% from the system, but rather switches the flow so that when it is below 180 the line from the trans is still open and flowing some. This keeps the cooler full, and avoids getting air surges in the line when it reaches temp.

Right now I give it a thumbs up, and recommend it maybe even for stock set ups. I also put an external filter in the line to catch the hated lock up clutch debris that can eventually bring down the lock up trans.

Sam

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Excellent report, Sam! I have had the same thoughts myself, but I have been unfamiliar with this product. Even if they say a transmission can never have too cool fluid, I have always meant that in any kind of machiery, a normal working temperature should be reached and maintained. The bypass method is ingenious. I'm gonna get one!

Olaf

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Aspenized

Something else I believe is true from reading the instruction sheet is that before it reaches 180, there is still full circulation of fluid, but 95% of it goes right back to the trans and does not enter the cooler.

Sam

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Yes, I read that too, ensures a quick warmup, while avoiding oil standing still in the cooler. Nice.

Olaf

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Aspenized