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nicky8668 · 10-27-2021, 06:58 PM

I found out this a couple of trip ago. Here is what’s going on:
After towing TT for a couple of hours in tow haul mode, unhitch and drive the truck alone in normal mod, the truck tend to hesitate when shifting from 3-5 when the tranny is cold. It feels like when it’s in 3rd and ready to upshift, went neutral for a second, then into 5th. It shifts fine after 5 mins. It’s also fine after drive the truck unladen for 50 miles, even with cold tranny. This only happen after I tow for a long trip then drive unladen. Any idea? Is it just how the tranny adapt?

nicky8668 · 10-27-2021, 07:06 PM

I forgot to mention I locked out 9 and 10 gears while in tow haul mode. But shouldn’t matter.

tuffr2 · 10-27-2021, 08:19 PM

Old school thought - check the transmission fluid level. Also check for a TSB on this problem.

nicky8668 · 10-27-2021, 08:42 PM

Quote:

Originally Posted by tuffr2

Old school thought - check the transmission fluid level. Also check for a TSB on this problem.

My tranny wasn’t the 1st gen which had problem. Dealer checked the tranny fluid, slightly low and they topped it off. The truck shift so smooth in tow haul mode under load. It’s just that first 50 miles unladen drive after towing. Weird.

NevadaNick · 10-27-2021, 09:12 PM

Modern transmission have adaptive learning and will continue shifting like it was towing until it learns the new driving habit.

Rhagfo · 10-27-2021, 09:41 PM

Quote:

Originally Posted by nicky8668

I forgot to mention I locked out 9 and 10 gears while in tow haul mode. But shouldn’t matter.

You don’t share much information about your TV or TT, not sure why you lock out 9 and 10 unless a gas 6.2 and 3.73’s and a heavy TT.

Arch Hoagland · 10-27-2021, 09:46 PM

Quote:

Originally Posted by NevadaNick

Modern transmission have adaptive learning and will continue shifting like it was towing until it learns the new driving habit.

That's exactly what I was thinking but don't know for sure.

tuffr2 · 10-28-2021, 03:08 AM

I can easily agree with the transmission has adaptive learning. But any system worth it's salt should recognize two shift patterns - one while tow haul mode is on and when tow haul mode is off. Again simply remember 2 shift patterns. Just add more memory and a little logic. Tow haul mode on use this shift pattern else use other shift pattern. Oh well - it does not sound like it does this, so I think it is the adaptive learning transmission.

I had a vehicle do this to me once and I thought the transmission was toast. Then I remembered I just changed the battery and the transmission needed to relearn the shift patterns.

nicky8668 · 10-28-2021, 07:06 AM

Quote:

Originally Posted by NevadaNick

Modern transmission have adaptive learning and will continue shifting like it was towing until it learns the new driving habit.

I thought that’s why we have tow haul mode and normal driving mode. It seems like each mode isn’t independent from adapting to different driving style.

nicky8668 · 10-28-2021, 07:08 AM

It’s 7.3 gasser with 3500 lbs TT. I tow in the mountains, constant 9-8 9-7 downshifting is annoying. Even on flat interstate, I rarely see it go into 10 in tow haul mode.

nicky8668 · 10-28-2021, 07:08 AM

Quote:

Originally Posted by Rhagfo

You don’t share much information about your TV or TT, not sure why you lock out 9 and 10 unless a gas 6.2 and 3.73’s and a heavy TT.

It’s 3.55 rear end.

nicky8668 · 10-28-2021, 07:13 AM

It’s really weird. If I drive the truck in tow haul mode unladen after a long towing trip, it shifts 1-2-3-4-5 much better. But under normal mode, it shifts 1-3-5. 1-3 is fine, 3-5 feels like 3-loss of power for half a sec-5 (slight hard shift). Feels like the transmission trying to figure out it should go into 4 or 5 from 3. It’s like the adaptive shifting memory told the tranny go to 4 like it’s towing a trailer, but live data says NO LOAD. Really weird 10 speed tranny. It shifts fine after driving it unladen for a while. Sigh.

Xmcdog · 10-28-2021, 07:18 AM

Quote:

Originally Posted by Arch Hoagland

That's exactly what I was thinking but don't know for sure.

Agree

Brantel · 10-28-2021, 08:57 AM

My 2020 and my 2022 do similar things when switching back and forth. Ambient temp can also change their behavior some. It all works itself out fairly quickly so I don't worry about it much. These trucks are way too smart/dumb/complex whatever you want to call it.