Ford Fusion Transmission Hangs During Shift


#1

2010 Fusion SE
2.5L 4 Cylinder
205K miles

The issue has progressively gotten worse over the last few years. More pronounced in the cold season vs summer. Also more pronounced between 3rd and 4th gear.

When ready to shift, the drivetrain hangs in limbo for a split second allowing the engine to rev before shifting into the next gear. Most of the time the shift is smooth, as seen in the video, but if this occurs with the pedal mashed it can cause some harsh shifting (I think as you’d expect). What’s my issue here? Seems like some sort of sensor but my googling isn’t pinpointing a sure-fire culprit.

Here’s a video to help explain: https://youtu.be/q-Bz4E05L10

Appreciate any insight, friends.

​​​​​​​-CK


#2

The first thing I always ask when this type of question comes up is, when was the last time the transmission fluid was serviced?

Tester


#3

To my knowledge the fluid has never been flushed or changed. 2nd owner purchased around 120k with no service records. Since it was past the 100k mark I opted not to change it… as I’ve had problems doing so past the normal service date with a previous car.


#4

Well? That’s what you end up with if you don’t maintain a transmission.

Start looking for a replacement transmission,or a replacement vehicle.

Tester


#5

Appreciate any other insight.

Thanks, friends.


#6

The way an automatic transmission shifts requires directing a high fluid pressure to some surface inside the transmission to force the corresponding clutches to engage. As the clutches wear it takes more and more fluid pressure to do that. The transmission is designed to accommodate for this, and increases the pressure as the clutches wear. But at some point the transmission pump just can’t produce any more pressure, and this is the symptom. A transmission shop can usually measure the fluid pressure at that point to determine if it is at the pump’s limit.

For all this to work the fluid level has to be correct and the fluid lines inside the transmission’s valve body have to be clean and the seals have to be intact and flexible. The pressures to make this work are super-high and that’s not happening if the seals are leaking even slightly. That’s why a proper transmission service could get it working again, new fluid will include additives that are good for the seals. That job depends on the transmission but often entails dropping and cleaning the pan, replacing the filter, and refilling w/fresh fluid, so worth a shot at least.


#7

Sounds like the transmission needs a replacement. Look for a good shop or two for a closer look and recommendations.


#8

And you’re wondering why a transmission with over 200K miles is acting up ?


#9

I’d start with a transmission fluid change to see what happens. If that doesn’t help, then I’d bring it to a good independent transmission shop (not a chain) for a diagnosis.