Question Trans Fluid Temp Spike??

Howdy gang!

I have an '02 7.3L with a Bank Intercooler, a Garrett 38 Turbo and an Edge Evolution. I regularly tow a 14k lb Toy Hauler without TFT issues. There's the occasional temp climb when I am hauling uphill on a hot day but it always cools down.

But yesterday while hauling on a 43F degree day, my TFT gauge spiked, the Check Gauge light came on, the OD override came on, and my Edge reported 280F degrees! This happened in a matter of minutes. The truck never went into limp mode but I felt that was next. I was fortunate enough that the Interstate exit included a Ford dealer so the truck is over there now. They are claiming there are no error codes to suggest a TFT sensor failure, but they want to remove the secondary trans fluid filter that was installed when the Banks was installed. (they also wanted to replace the factory transcooler but it looks fine).

Here's the thing....a few years ago I had the exact same issue but, in that case, the truck went into limp mode. The Ford dealer reset the code and the issue never occurred again. They claimed it was likely a "stuck" condition on the TFT sensor and that it was not that uncommon to see. Here's the other thing...I just had the solenoid pack with the TFT sensor replaced when I had some transmission work done. But that was over 500 miles ago without issue, until now.

I welcome your thoughts on whether the Ford dealer here ha a clue or not.

Have you had the bypass valve replaced or serviced? That could have gotten stuck and caused a no-flow to the trans cooler.

bcvickers said:

Have you had the bypass valve replaced or serviced? That could have gotten stuck and caused a no-flow to the trans cooler.

Click to expand...

BINGO! The dealer just introduced this idea and this seems like the most reasonable explanation. We're going to do this and see how it goes. Thanks!

I have a 2002 7.3 that has been modified, and this happened to me when I was towing a 14K lb. 5th-wheel up a mountain (@ 70 mph). I looked down and saw the trans temp spike, so I immediately kicked off the cruise control and moved over to the right lane and continued at 55 mph. The trans temp dropped back down to its normal position on the indicator. Turns out, the stock converter was slipping. Typically, when you make mods for performance, it shows up in other areas, in this case trans and converter. I've since installed a heavy duty converter, valve body and clutches, as well as an over-sized trans cooler and the means to monitor things ( trans temp gauge). I haven't had any problems since.

The one thing that many forget to do. When doing serious modifications many things have to be upgraded to deal with the increase torque and horsepower. If they are not it is just a matter of time before slippage or worse happens. And of course it never happens in a convenient place.....Murphy's Law!

Did you cook the transmission fluid? What kind of fluid are you running?

I put an aftermarket trans-cooler on my 99.5 when this happened.