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5r55s P0755 - Not the first and sure won't be the last


Elite Explorer
October 11, 2015
Reaction score
New Jersey
Year, Model & Trim Level
2006 Mountaineer Luxury
Let's start off by saying I'm a chef not a mechanic but determined to learn to fix what I can. I got the check engine light on with with abnormal shifting. Pulled the code and got P0755 after some research decided to try the servo bore repair kit. (Little note that is a real struggle to do with the transmission still in the truck but if I can do it, anyone can. )

P0755 is only code showing and also I do not get blinking O/D light but I also do not get 2nd gear or O/D to engage at all, skips from 1st to 3rd and stays in high rpm 5th.

After repair kit I reset code, still get the shifting issues. Check engine light came back and now a whining sound when cold start...it eventually goes away. This weekend I decided to change out solenoid pack and filter / fluid change. Fluid was dark and unfortunately there was some metal in the pan but nothing extreme. I did the solenoid install, washed out pan, reinstalled (broke a pan bolt which I'm struggling to find but I'll get one) and cleared the code. The whining noise is gone, it shifts smoother but still skipping 2nd and O/D. I have not done a band adjustment yet but will try that today (sounds a bit confusing but I'll figure it out)

Wondering if anyone has any ideas, I will probably try valve body next, I think it can't be much more difficult than the solenoid. My issue seems a little different than others since I'm getting only the one code, my light does not blink (actually sometimes won't go on when pressing the button).

Other than that the shifts are pretty clean but highway driving at those high rpms can't be good for engine or the gas mileage.

Love this forum and have learned tons from you all...if I can help anyone less experienced than me on repairs I've done so far...just ask.