AT Shifting poorly when cold

[BlueCollarDaily]

Yes, my 19 did this too ( I had high hopes the 25 is better in everyway and a LOT faster for whatever reason according to the dragy pro ) but the 19 also progressed from this exact thing to having a LOT of delay when cold ( warm up 3-5 minutes, now i was told then it recirculates the fluid till its a certain temp before it even sends it thru the cooler ) between R to D, then this exact behavior....then it started whining ( there is ZERO whine in this one yet ) like a power steering pump low of fluid...
That ended up being a full valve body which fixed it, then it started again few thousand miles later, and another valve body again it fixed it....till a few thousand or so miles later then I out of pocket took it to a local Ford trans expert ( still new to 10r80 but known for his 6R80 builds and sharp ).
He tore it down clutches were gone and shift solenoids seemed to be the culprit, a bearing race was out and yes another valve body because what was happening is they were being contaminated when the dealership changed them with the clutch material that had begun to accumulate.
He machined it in house to accept the Raybestos GPZ clutches, cleaned it all, flushed all cooling lines and yes another valve body ( still.had to get Ford.to marry it to.the car ), it never gave me or the next owner another problem at 720whp I got reports up to it had 57k miles on it 2 years later......
I had read the 25s had several revisions and indeed it seemed improved in every way but unfortunately I know how this ends as ive lived it......he did R n D and prices in 2019 much better than now...im fairly sure its gonna be quadruple what it cost me then, its a damn shame.....
No your right its not normal cause ive seen it over and over again and lived it, it also didnt do it zero for the first 3000 miles it DEVELOPED, which indicates its not even normal for IT......for the record my 19 and every single person I talked into checking the fluid correctly ( my ford dealership did not ) WAS indeed 1.75qts low and that does help...I should have had my trans guy break the seal on the gap and check it correctly ( full temp and driven thru all gears, running on a lift from underneath) on the first day but it was perfect..

Its imperfections/leaks/then material slash weak coils in the valve body solenoids that causes this, if your lucky when it warms up it seals and works correctly for a time.....
Sigh.....after 6 years I thought it was addressed.......Ill save up and get the upgraded billet replacements...the trans guy is now very familiar with em but it will cost what a super charger would to repair correctly now....and trust me when I say it CAN be made to NOT do this cold or warm it just takes a lot of money.......damnit

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[ZXMustang]

One data point to add, I own three other 10R60/80 Ford vehicles (not mustangs), and they all shift like dog shit. Our 25 explorer ST bogs and lugs and jerks at times and its pretty standard.

 

[BlueCollarDaily]

One data point to add, I own three other 10R60/80 Ford vehicles (not mustangs), and they all shift like dog shit. Our 25 explorer ST bogs and lugs and jerks at times and its pretty standard.

Mine is less doing that ( and the 19 before it, and im old man it was explained to me in detail what's happening and as I said the upgrades DID stop it ) than its slipping OUT of gear as if you pushed a clutch pedal in on a manual totally stops pulling, rpm flares up, then goes into next gear and may or may not skip shift ( this was a departure from 19 which skip shifted as a "feature", I immediately at the dealer noticed the 25 did NOT skip shift in normal like the 19 ) to 5th....its all valve body casting, sealing, separator plate, iirc it had 6 solenoids on it that prscharge the next gear and release last in timing...they are a marvel hell they will hold a 1000hp and not break hard parts ( but clutches wont take it ).
If ANYTHING from VB plate straightness to porosity, solenoid firing time/coil strength isnt perfect then its unable to manage smooth shifts, those have have it only when cold likely ( as was my case ) have leaks that are sealing when it expands, im not a trans expert ive built power glides, turbo 350/400 4l80es but the mind is going...
I can tell you what's coming next if it follows ( and so far it is, except it had vastly improved scheduling from the 19 and until now was spot on cold or hot, or close enough to it not to be alarmed ) the other 3x ive dealt with this, it will start to not engage from R to D until it really warms up....and downshifting will becoming as clunky even harsh and the slipping on upshifts......
The trans has a lot of potential did you know the filter ( at least the one for the 19 ) has a dissimilar metal valving that redirects cold fluid ( ULV its real thin) thru one micron size when its cold and another when its warm? Im bummed cause it was SO perfect and I wanted to add boost not billet valve body/parts hehe....ill say this even with this issue imho they improved everything over the 19....its way faster dragy hits bone stock p255 all seasons 12.3 119mph, full air pressure, old dusty 2 lane, WAY faster than my 19 was in the same test spot and my 25 is a 401a with heavy active exhaist the 19 was a 400a I immediately X piped and MBRP cat backed ( eventually boosted )...

If it did it from day 1 I could live with it better, it just starting to do it at 3000 miles is the indicator something changed....it will get worse likely I'll update this if ford does anything reasonable....

 

[NJWeatherman]

Hey guys. I have a 2026 Mustang GT Premium, A10. I'm closing in on 1,300 miles.
Here is what I have noticed so far with the A10:
On the first drive of the day, if I take off in Sport mode, 1st gear hangs and when it finally shifts into 2nd, it is harsh. It's definitely throttle sensitive. The next shift is less harsh, and then it drives fine.
If I take off in Normal mode on the first start up of the day, no problems whatsoever.

Does anyone know what temperature the A10 transmission is when it is finally warmed up?

 

[LouG]

Mine runs around 65C to 80C in normal street driving. I always start driving in engine/trans normal mode.

 

[ZXMustang]

This is normal until the trans gets to 140f. Drive it nice and enjoy it once the trans fluid comes up to temp.

 

[Will2]

One thing that surprised me on my new '26 (versus 2 prior '25s and a '24) was the trans shifting feels noticeably different (smoother). I get less of the "stumble-into-5th" and more rough downshifts into 9th/8th that didn't happen on my '25s/'24. So my conclusion is Ford actively continues to modify their programming for these through the model years, even if it's unannounced. Really makes me want to always wait for the last model year of a generation/refresh. I've also noticed different patterns of interior rattles from earlier builds to later builds, different patterns of cosmetic defects (i.e. some '25s and '26s have paint chipping/rubbing on the corners of the bumpers where they meet fenders/quarter panels because the factory attached them TOO tight). So these cars and their builds are changing throughout each model year, even if all specs stay the same.

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