2005 Expedition - Transmission 'hunts' for correct gear at 45 mph

[cason234]

Hello Expedtion Enthusiasts!

My 2005 Expedtion exhibits the following symptom, and I hope you can offer some good advice.

Car has 140,000 miles. I've had it since 59,000 miles. I've changed the transmission fluid using AMSOIL ATF twice since I had the vehicle, and both times fluid was bright red, and no unusual smell.

When driving at around 45 MPH, and with light application of throttle, the transmission seems unsure whether to use 3rd or 4th gear, and it quickly toggles between the two. If you back off the throttle, it stays with 4th. If you hit the throttle more aggressively, it confidently selects 3rd gear, and smartly shifts into 4th at the right time...... so, in summary, there is a part throttle 'indecision' on the part of the transmission. It doesn't slip, it doesn't flare up between shifts.....

I'm hoping this is an electronic sensor / solenoid or something along those lines. Anyone else experience something like this, and what was the solution?

Thanks in advance for your help.

Cason

 

[1955moose]

Transmission hunting is usually your engine with a misfire or intake leak. That or a partially clogged injector. These things can fool the trans, and torque converter, and cause the hunting between gears, particular 3-4. Smoke the motor, be sure you have 0 vacuum leaks. Wouldn't be a bad idea to run any codes that may pop up.

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