Feels like the transmission is slipping

[curry67]

if the car is ever at like highway speed or over 50 it like feels like its shaking or slipping at 1800-2500 rpm. It usually when im in 4-5-6 i think mostly 5th. Is this a transmission problem? I have seen a blinking engine light when this first started happening i brought it to a ford dealership they said it was good but it still does it. There wernt any engine codes. I almost feeling like doing it over and over till it blinks again so i can bring it in.

If i floor it feels great 98 percent of the time but it does happen once or twice. its only when the revs or low.

[DJE624]

Could be some sensor on the transmission.  Can you check for codes?

[EcoBrick Bob]

Might be a misfire... It won't code until you get a solid "check engine" light.

[DJE624]

I have pulled codes w/o a check engine light. 

[EcoBrick Bob]

It's possible, but I have had a flashing light like that and after 3 times over a few weeks, I finally got a solid light and a #6 cylinder misfire.  And... when vehicle is misfiring, it shutters just like described.

This happened when I was going down hill for  several seconds, where tranny was doing the braking.  Once flashing, when you attempted to accelerate, car shuttered till misfire went away.

[curry67]

no im unable to check the codes myself i think i will be buying one of those things forsure though. It only happens when i like really ease into it. like if i dont press hard enough to make it downshift.

[DJE624]

If you have an AutoZone nearby, they will check it for free. Maybe other part stores would too.

[SHOdded]

This TSB may address the "slippage" issue:  http://www.fordservicecontent.com/Ford_Content/pubs/content/~WT/~MUS~LEN/3650/tsb10-09-09.htm

"broken orifice restrictor cup plug in the forward clutch circuit"

[BiGMaC]

curry67... what's model and year of your ride?

[curry67]

2010 non pp. advancetrac on.

[BiGMaC]

If it's the tranny, while other causes could be at the root, the TSB SHOdded posted below is the one you want, including what Ford recommends for diagnosis and repair.

Maybe make a signature so people can tell what you're driving. 

[jimmyducati]

I had the exact same issue you described, started after I upgraded to the 4+ tune from LMS... Called them and they said it could be "spark blowout" from the extra boost and improperly set spark plug gaps, others here said its probably a misfire from possible combo of things that I fixed all at once.

First thing, change the spark plugs and gap them properly, something ford seemingly never did. The gap should be .035..

Second, and the most probable cause of your problems, there is a wire that is unshielded that runs vertically up the front corner of the drivers side head. This wire is the knock sensor and has been known to chafe on the sharp edge of the head causing a short and consequently triggering the misfire your feeling while driving down the road. WRAP THAT WIRE!

I had these symptoms 3-5 times a week, haven't had them in the 2 months since I applied these fixes.

[BiGMaC]

jimmyd... could you post a pic of the knock sensor wire...? TIA

[DJE624]

[BiGMaC]

Thanks DJ   

What a terrible piece of engineering!     I'm gonna make it a point to put the wires in a sleeve and the a loom to stand them off of the metal