Transmission Cooler
Ok, so I've got a 2002 F150 with the 4.2L V6, I recently ordered a Derale Class IV plate and fin transmission cooler for it. Everything seems straight forward, any tips, tricks, secrets, or anythin...
Forum Discussion
Most of the more recent transmissions have a thermostatic valve, so fluid goes out to the coolers only when it gets above operating temperature, a lot like the engine coolant thermostat. This allows the transmission to quickly reach and maintain proper operating temperature.
This is why the above poster jodeb720 continues to see the temperatures, the transmission is purposely maintaining operating temperature. The extra coolers are useful for high load conditions like climbing and for quick recovery following high load conditions. The 6R75 in my Expy warms to 195 in the driveway under zero load, and then stays there. Both the transmissions and the newer fluids have been designed for this.
This is also why flushes are not as effective on many newer transmissions, to get flow you have to bypass the thermostatic valve, or get the fluid hot enough for it to open, which is very hard without actually driving the car. In my case, the thermostatic valve is inside the case so it cant be bypassed. A flush machine is pointless. Just drain and fill.
One other note, the above post regarding the water oil vs air oil heat exchange is correct. The water oil heat exchange that takes place in the bottom of the radiator is substantial, and it happens no matter how fast the car is moving. The oil air coolers have to be massive to accomplish the same heat transfer as the water oil cooler, and the vehicle has to be moving to create the airflow. If you are pulling a steep grade, or backing into a campsite, those oil air coolers are not effective.
This is why the above poster jodeb720 continues to see the temperatures, the transmission is purposely maintaining operating temperature. The extra coolers are useful for high load conditions like climbing and for quick recovery following high load conditions. The 6R75 in my Expy warms to 195 in the driveway under zero load, and then stays there. Both the transmissions and the newer fluids have been designed for this.
This is also why flushes are not as effective on many newer transmissions, to get flow you have to bypass the thermostatic valve, or get the fluid hot enough for it to open, which is very hard without actually driving the car. In my case, the thermostatic valve is inside the case so it cant be bypassed. A flush machine is pointless. Just drain and fill.
One other note, the above post regarding the water oil vs air oil heat exchange is correct. The water oil heat exchange that takes place in the bottom of the radiator is substantial, and it happens no matter how fast the car is moving. The oil air coolers have to be massive to accomplish the same heat transfer as the water oil cooler, and the vehicle has to be moving to create the airflow. If you are pulling a steep grade, or backing into a campsite, those oil air coolers are not effective.
