I've got a 2002 Lancer with an automatic transmission. It just started shifting hard, hard enough to give you whiplash.

I've tried scanning for codes, and none were found, checked fluid level and color, and everything was good. I did remove the battery cable to reset the ECU and the transmission started shifting perfect for about 5 minutes and then it started shifting hard again. So I think that it's some electrical issue.

Does anyone have any idea on what it could be or what I can check?

 

Sounds like your input and/or output sensors are on their way out. These sensors are used to tell the computer what the speed of both sides of the transmission are turning at in order to determine when to shift (that along with some input from various other sensors that is) Usually they will throw a code though...

 

Is there anyway to test the input/output sensors?

 

I was also going to suggest the sensors but no code does sound weird. How long has this been going on?

 

It just started from one day to another. Parked it overnight, then drove away in the morning, and BAM! I almost thought I was going through the windshield.


I did forgot to say that when I reset the ECU, it was fine for the 5 minutes and then gradually started shifting harder. Not sure if that helps.

Oh another thing I forgot, it only shifts hard from the 2-3 shift and the 3-4 shift.

I've learned when to let go of the gas, and it'll shift softer.

 

Could also have to do with the shift solenoids although unfortunately I cant give much help on testing any of the solenoids or sensors not sure how.

 

Now that sounds like input speed sensor. Mine did the same thing.

 

Did yours throw a code? So yours also shifted hard from 2-3 and 3-4?

Anyone have the part # for the input sensor? How much is the part? Also, anywhere I can read on how to remove the input sensor?

 

Check out the full service manual, a quick google search should lead you to a thread here on evoM where you can download it for free. If you have no success just PM me and I will email or hook you up with a link to the file.

 

Thanks for the info. I found the FSM, but the only mention of the speed sensor is one picture of the location.

 

Search in this forum for transmission acting crazy. There are two threads here about it.

 

Well I just went ahead and ordered the input sensor without there being a code. I hope that's the problem. I'll update the thread once I get the sensor installed.

 

To update the thread: I got the sensor, and switched it out. Took it for a quick 20 minute drive, and it shifts good now! Unlike when I disconnected the battery and it gradually started shifting hard again after 5 minutes.

For reference, I used a Dorman 917-610 sensor. I'll drive it more this weekend and I hope everything is fixed. I'll report back just to give an update, and just in case someone has the same issue.

 

Everything is working perfect. Thanks again everyone.

 

Glad we could help.