Water is better at transferring heat than air. If you heated a piece of metal cherry red with a torch and wanted to cool it quickly, would you drop it in a bucket of water or set it in front of a fan? Bypassing the cooler in the radiator is a mistake.

 

I am Installing a new 46RE this weekend, and Transmission Depot will not honor my warranty if I don't replace it since it wouldn't flush. The radiator is designed to heat the fluid on cold starts, the coolant is almost always HOTTER than trans fluid should ever be to begin with. (This Georgia heat has my engine running close to 200 in traffic)

 

The temp sensor is where the hot coolant leaves the engine, not the temp of the cool side of the radiator. Why can't you flush the cooler in the radiator? Kooler Kleen is recommended by transmission shops. I'd keep the radiator cooler and add the one you bought after it.

 

radiator is designed to heat the trans fluid more than cool it. My trans runs at 150 deg with the radiator circuit bypassed (ive had it bypassed for 8 year with no issues). Like mentioned before, bypassing the radiator heat ex changer is not a problem unless you live where the ambient temp dips below freezing often.
To the OP - bypass the radiator heat ex-changer and add your new aux cooler. If you are ditching the factory cooler (between the rad and conden.) then be sure to add even another aux cooler like you just bought.
Also, removing the check valve in the trans line before the radiator will help too if you havent done so already.

 

I was able to fully flush my factory Aux cooler between radiator and condenser so I kept it and added my new one as well. I also removed the check valve, which I kept just in case lol. I still need to add a trans temp gauge, Where would the best place for the thermostat to go?

 

There was a blockage of some sort in the heat exchanger, but the kooler kleen did do a great job at flushing my factory aux cooler between the radiator and condenser.

 

Lots of options for temp gauge. On the newer trucks, PCM is aware of trans temp. Some apps will actually even tell you. (torque is one, I think.)

 

cjames- I installed my trans temp gauge sender in the accumulator test port. While a pan with a bung for a temp sender would be ideal, i chose the accum. test port because it always has fluid/pressure passing through to give a realistic tranny fluid temperature.
Here is where its located- just unscrew the test port plug and screw in the temp sender. The sender that came with my Autometer trans temp gauge was the correct thread pitch.
https://www.google.com/search?q=46re...5UHHE2OrDToMM: