Ford Flex Rough/Hard Shifts after towing 4-down

[ficodek]

I've towed my 2013 Flex Limited AWD close to 40,000 trouble-free miles 4-down behind my motor home...until this week, and I'm wondering if anyone else has seen this same problem:

All towing is done according to manufacturer's instructions. I am careful to run the car for at least 5 minutes in the morning before towing it, including cycling between the gears. If I'm going to be on the road for more than 5 hours I repeat this process at mid-day.

2 weeks ago in the Black Hills of South Dakota, I got a check engine light. The code said bad bank 2 02 sensor. The incredibly unhelpful Ford dealer I went to said it would take 1-2 weeks to get a service appointment. He erased the code and said I could probably still drive it and maybe it would turn out to be a transient event (hmmm). Since I was on a tight schedule, I continued on my way and hoped for the best.

2 days and 600 toad miles later, I unhitched the car and got ready to drive, only to experience very hard, rapid jerks and bangs from the transmission as I moved at low speed around the campground. Pretty scary, actually. I drove, very gently, around the surrounding roads to see how if we could survive with it this way, and found that in upper gears it ran just fine. Stops and starts would still be noisy, jerky affairs. But after about 10 miles of driving, everything smoothed out.

The next day and 350 toad miles later, the same thing happened, only it seemed worse. I really thought the car unsafe to drive, and hoped to be able to get to a Ford dealer about 20 miles away. By the time I got there, the car was shifting normally, so there really wasn't anything for the dealer to look at. I went on to drive it about 100 normal miles today.

I should add there are no codes in the car either that could indicate the cause.

Has anyone else experienced this behavior? What was the cause? Could the previous 02 sensor issue in any way affect how the transmission shifts after being towed? Could it be a computer issue? I'm really stumped...the transmission is shifting totally normally now, so I don't feel like it's about to fall out on the ground but I have no idea where else to look.

Thanks for any help/advice/ideas!!

[Skip426]

I don't know if all electronic transmissions will do this , but rough shifting during start up after battery disconnect is common on Chrysler products.

The point I'll make is battery disconnect isn't always the cause , low battery voltage during engine cranking can do the same thing , if the battery voltage available at the trans controller drops below 10 volts during engine cranking then all the learned shift data in the controller is dropped and needs to be re-learned by driving/shifting for 10 mins or so.

Have the toad battery load tested, would be the first step.