Update...
Dealer called.. found 6 stored codes.
the significant one was code U1012. Dealt with communication with maps and modules.

They found clear heat shrink on one of the lugs at the battery connection. They said there was a recall to be done at dealer pre-delivery. Mine was never done. So there was resistance causing low voltage and communication issues. Makes sense. Heat may have aggravated it.

So glad it was not related to heavy drive line issues. The concept of tearing into things assembled on a production line makes me sick!!

Hopefully it's fixed!!!

19 XLT 4X4 3.5 EB. 1700 miles
While towing our 7k lb. travel trailer last week noticed several items

Descending a grade, in tow haul mode, trailer connected it down shifts to attempt control of the speed. Nice feature.. but it would not release and upshift unless I put it in neutral then back to drive.

I had the wrench light come on and the warning
Powertrain malfunction/reduced power.
Powertrain, 4wd or all wheel drive fault.
Turbos kept functioning and no noticeable decrease in performance. Light stayed on until we got home. After several restarts light went out.

the trans has what I thought was just the normal high pitched whine.

I have an appointment for next week.

I was wondering if anyone has had this and if it was the secondary transmission pump

thanks in advance
pete

 

1st I don't have a 10 spd....but am wondering (important to mention) if by chance the Rpm was such that it would not go into gear.
With my 6 spd the computor is supposed to not let it over rev by going in a lowerr gear??

 

I noticed long ago my 2019 xlt 5.0 will downshift going downhill IF you are in cruise. take it out of cruise and it will stay in the same gear.

 

In tow haul mode, with trailer attached. When engaged, it will even downshift in city traffic when you approach a stop.
good feature, it just sticks in 2nd or 3rd gear1 out of 3 times
I'm sure that's not right.

 

Keep us posted of your findings. I will be towing my similar setup soon, and I have less miles than you.The wrench light would have freaked me out as well. Glad it made you home, hopefully just a reflash of some electronics.

 

Again in Tow / Haul if you tap the brakes while decelerating or coasting downhill the transmission will downshift in an attempt to engine brake. The high rpm and load on the transmission cause the transmission and engine coolant temperatures to rise. I found this out on my truck while towing though New England mountains. I had to stop the truck and put in park, let it run at idle to lower the temps and to get it to shift to a higher gear again. After a few instances I learned. I don't see the point in this feature with the Ecoboost as there is little engine braking effect.

 

Just give it some gas and it should up shift, But maybe something is not right.
Let the dealer look at it.....

 

Yep, that's the logical thought. It doesn't upshift,
you could peg the tach... but I'm smart enough.

it goes in Wednesday, I'll report back.

 

If the wrench icon came on, obviously something is wrong. Let service figure it out. May be something as simple as a program update.

 

What automatic transmission does NOT downshift when approaching a stop.
That sounds like normal behavior to me.

I'd say not to be shifting to neutral and back at highway speeds. If the power train error lights came on around this same time of behavior, perhaps it's related to that. It wasn't clear if the check engine light was timed with the shifting to neutral situation you put it in.

I'd concur that cruise control controls the hill descent, however I don't have a 10 speed and haven't connected a trailer. However my 6 speed will do that under normal driving conditions with cruise active on steep grades.