Transmission shudder/surging

[Mrwrench2]

Hey guys,

2010 SHO non-pp. 145,000 miles.

Recently, the car has begun to shudder at light throttle right after the torque converter lockup in 3rd gear. Sometimes somewhat violently. If you power through the shudder it will smooth out. Doesn’t happen at wide open throttle.

Fluid level is ok after checking it hot.

It also displayed the signs of a bad Transmission Range Sensor recently, by slipping out of drive and also not displaying it was in park after a cold start with the associated wrench light on the dash.

Thoughts anyone on the TRS?

 

[Markboni55]

Check your plugs and coil packs. A miss-fire can cause a very similar feeling and lead you to believe it's transmission when not at all. Just giving you another avenue to chase the rabbit down the hole lol. Hooking it up to a diagnostic software is your best bet. When is the last time you replaced the PTU oil?

 

[SHOdded]

Possibly TRS possibly TC, or both.  TRS is easy to check - Ford issued a TSB with what connector, pins,and resistance values to look for.  The TC is trickier but I am sure tuning devices can log transmission behavior.  Probably Forscan Lite can as well on the 6F55, I know it can on the 6F50.

 

[Mrwrench2]

I’m going to change the plugs over to Motorcraft SP-534’s today. Pulled one of the plugs and it was a Denso ITV22 (I believe one step colder plug) and the gap was all the way up .050 and oddly worn.

I’ll also be draining and filling the transmission, and I’ll test the TRS while I’m down there.

I’ve attached photos of the plug for you all to take a look at.

 

[SHOdded]

cant ever go wrong changing plugs on an ecoboost as per Mark's suggestion above.  Hope that is as deep as it goes!

 

[Mrwrench2]

TRS tested bad (not surprised, had all the tell tale signs of failure).

Changed the spark plugs to Motorcraft SP-534, gapped at .030. Drained 5 quarts from the transmission and replaced with Motorcraft Mercon LV, and suctioned out the CAC which had 3/4” of fluid using the dipstick test.

The problem hasn’t subsided completely, but certainly has improved. Old plugs were showing a .050 gap and looked very worn.

 

[ZSHO]

TRS tested bad (not surprised, had all the tell tale signs of failure).

Changed the spark plugs to Motorcraft SP-534, gapped at .030. Drained 5 quarts from the transmission and replaced with Motorcraft Mercon LV, and suctioned out the CAC which had 3/4” of fluid using the dipstick test.

The problem hasn’t subsided completely, but certainly has improved. Old plugs were showing a .050 gap and looked very worn.

That sounds like a good amount of oil,fuel inside the CAC! Did you jack up the drivers side! 
I would add some new COP to the list especially if original! Some preventative maintenance goes a long way.  Z

https://www.rockauto.com/en/moreinfo.php?

https://www.rockauto.com/en/catalog/ford,2013,taurus,3.5l+v6+turbocharged,1503823,ignition,spark+plug+/+coil-on-plug+boot,10150

 

[Mrwrench2]

Yes, I did jack up the drivers side of the car.

This is 145,000 mile car with 5 owners and 2 prior accidents. Needless to say, she’s lacking the service history (aside from the PTU replacement at a dealership 30k miles ago) and she’s overall in need of some TLC. That being said, I did also add a small bottle of Dr. Tranny instant shudder Fixx to the transmission fluid this afternoon, and the shudder was immediately resolved.

I think I know what direction I will be needing to go now. Time to start saving for a Torque Converter.

 

[SHOdded]

Doing things right :thumb:  Very glad to see!