Hairy McScary - Power Shrift attempting 3rd to 1st downshift

[AlCan]

Hi Guys,

My current daily, of the last few weeks, is the '13 MC TDCi DCT Wagon I've mentioned in relation to Cam Chain lubrication. That's seeming much improved now, but another problem has been rearing its ugly head.

"Randomly", averaging about once every 100-200km, during routine decelerations below about 25km/h, the transmission has been throwing a wild "downshift". Suddenly, instead of its gentle downshifting through the gears at just above idle speeds, it suddenly seems to attempt an early shift into first, and the engine revs up to 2,000-3,000 RPM. It's as if the Kick Down Switch has suddenly been activated. Fortunately, it's either in Neutral or the clutches are disengaged as, so far, it doesn't start powering into the back of the car in front. It's alarming all the same, and you can understand why anyone would be unhappy.

As I see it, the only way to sort this out is with FORScan, and now have a Windows version with an Extended (Free, 2 month) Licence - a great response to previous sanctions? Still figuring it out, and already discovered you apparently can't graph more than 12 traces, and you can't scroll up to view the lower ones. If anyone knows how, please let me know.

On my first crack at this I selected 14 PIDs, but fortunately, you can still access that data, even if you can't graph it.Took the car out yesterday, down a street with a mile of speed humps - the perfect excuse for lots of realistic slowdowns and speedups. On the first run, last hump, got a result. Saved it, figured I was damn lucky and headed home. Damn it if I didn't get a much bigger example just approaching a set of traffic lights. That time (the second since I've owned it), the trans got "stuck" in first gear and I had to crawl around the corner to get out of the traffic. Wanted to resume recording but it sorted itself out before I could do anything. Started recording again and it then did another "normal" example which I'm showing here, though not all the traces are visible.
https://photos.app.goo.gl/xCF7fpJZqVA4KTm28

Unfortunately, it looks as if the "GEAR_SEL" trace has a bug and doesn't show the gear steps properly, but it does show an unexpected shift into Neutral at the time in question. (The raw data shows the actual gear steps.) This coincides with the highest engine revs of the trip, and looking at the raw data seems to show that the firmware attempted to select a change from 3rd into 1st.

As we know, these two gears are both on the same input shaft and clutch, so such a change should not really be possible. That's to say, a Pre-select, Dual Clutch change would not be possible, though I guess, a single clutch 3-N-1 would, in theory. Maybe, it is actually implemented, but what's causing it to activate? I logged the KDS PID, but that's as it should be, I think. It seems to go active when in Park... Is that normal?

I can confirm that throughout this episode and the engine rev up, I didn't touch the accelerator and maintained my foot on the brake pedal. The engine rev up was obviously commanded internally, like it is during normal downshifts. Except this is a bit extreme.

So, can anyone suggest what the problem here is? I'm guessing that, like in Mondaveo's experience, this problem has existed through the past two or three ownerships.

One thing I notice from the raw data is that the (PCM) Engine RPM and the TCM Engine RPM data begin to differ by around 200 RPM during this craziness. Unfortunately, I can't seem to see which column is PCM and which is TCM (at least, not in off-line mode).

Anyway, could this be related? Any thoughts, anyone?

P.S. I didn't capture any new DTCs yet. Forgot to check after this 'successful' trip. (It does have a historical P0766:00-28 Shift Solenoid 'D' Performance/Stuck Off and a P0700:00-28 Transmission Control System (MIL Request), but these were from when I bought it, when it was suffering from very severe [undriveable] EGR issues. I assumed, maybe wrongly, that those aren't relevant to this.)

Event begins at time 55,384ms when Trans in 3rd gear, targets a change to 1st gear.

The engine starts to rev up at 55,424ms, but I don't know why the other Eng Speed trace was leading but now starts to lag. Is it that the TCM Engine Speed is not actually engine speed but clutch output speed? So clutch was slipping / disengaged?

I have the previous Service Docket, serviced by a Ford dealer 20,000km ago. Says "REPLACED TRANSMISSION FLUID AND FILTER", Parts include 6 litres of "TRANS FLU 75W 936A", P/N 'AXT13LDC'. Sound right?

Can anyone tell me how to read Firmware levels / is there an update?