Derale 25791 Fluid Control Thermostat Kit , Silver

Coolers for transmissions are a low-cost insurance policy. The transmissions used to shift a lot harder in cold weather before I discovered this thermostat. This should solve the problem, and I can already tell from the shift quality and sensor data that the transmission warms up to operating temperature quickly, just like it did before the cooler was installed, even with lows in the 40s. Other cars don't seem to warm up their transmissions in sub-zero temperatures. The weather is extremely cold. br>I like how there's a small amount of fluid leakage past the thermostatic valve to keep things moving. Using an infrared thermometer, I can see that the trans cooler is maintaining a temperature close to ambient, while the hot side of the valve warms up. Then, around 155, I notice the trans cooler begin to warm up a little. I've loaded up the minivan and am towing a boat, and the trans temp won't rise above 180 degrees. It's doing its job. The thermostat can be mounted vertically or horizontally using the bracket. The threads appear to be 1/4" in diameter. Thread locker is a great tool to have. I didn't use the bracket in the end, but it was nice to have on hand in case I needed it. I didn't think it came with sheet metal screws to attach the bracket, so I used hardware store hose fittings instead. If you want to void your warranty, it appears that you can unscrew the top, unscrew the thermostat, and remove it with a crescent wrench. I haven't tried it, and I'm not sure where you'd find a different thermostat, but it appears to be possible.

Jeremias Middleton

| Mar 16, 2021

Due to the modifications I made to the transmission, I installed a very large trans cooler on my car. a high-stall converter that generates a lot of heat when accelerating quickly or climbing long steep inclines in the mountains Under normal circumstances, however, I couldn't get the trans to go much higher than 130 or 140 degrees, indicating that I was a little too cool. The transitions were not as clean as they could have been. br>br>After installing the fluid thermostat, the transmission will warm up to 180 degrees after a short time, and the shifts will be crisp and chirp the tires as they were designed to. Observing the temperature gauge on the transmission, it appears that it begins to open around 180 degrees. So far, everything appears to be working properly, and there are no leaks around the thermostat block fittings. br>br>Overall, it's a good product so far; the only issue I had was that the mounting bracket that came with it didn't work out for my installation, so I had to make my own bracket; that's about the only drawback I can think of. Winter will arrive in a few months, and that will be the true test of how well this works for transmission warm-ups, but based on how well it is working now, there should be no problems with warm-up. I would advise anyone installing an external trans cooler that is not connected to the car or truck's radiator to do so because, just as heat can be your enemy, so can overly cold temperatures.

Navy Solis

| Mar 11, 2021

In the summer, I put a tru cool 40k on my Sierra and it did exactly what I needed it to. When it's in the triple digits and I'm towing a camper, I'm shaved down by 40 degrees. It does, however, excel at shedding heat far too much. In 110 degree weather, pulling my boat up the steep roads out of the marina, it never got above 180 degrees and dropped like a rock to 160 on the highway. In the winter, when it gets colder, I have to completely close it off. br>br>Place the thermostat in the desired position. In 90-degree weather, I could only get it to 172 degrees Fahrenheit, and when you're not in it, it drops to 168 degrees Fahrenheit. This is exactly where I wanted my temperatures to be, and in the worst-case scenario of towing, I don't expect it to ever get above 180 degrees, which is fine by my transmission. Dorman 800 was used. For my installation, I used 606 trans fittings. Like the rest of my truck's trans fittings, they're 3/8 npt to 3/8 quick connect.

Carl Bernard

| Oct 26, 2021