Shawn T

You’re right, I used the manual function and figured out the rough downshift was from 3rd to 2nd. This is my fourth Allison tranny and all of the other trucks were bought new as well. It seemed like they were hurky jerky the first 400 or so miles. It’s just really sporadic. I hope it smooths out

Update: 300 miles and smooth ride but Allison downshift from 2nd to 1st is violent every 2 or 3 stops, not sure why any thoughts?

Wow ok maybe I’ll pay closer attention but I swear it’s as smooth as silk. I see either a recall or TSB coming. My Allison has learned and shifts are now clean and transparent

I have not, in fact it's the smoothest driving truck I have driven. I thought my 15 was smooth, nothing compares to the 20.

Hmm, I updated my profile, but old pic an info are still there?

So Tuesday I took possession of my long-awaited order. '20 Sierra Denali Ultimate HD Duramax 1. Completely different truck from the ground up! 2. Ride and noise reduction quality even better, if you can imagine 3. Seats and field of view is like riding in a panorama, just amazing 4. Rear view mirror camera is insane, you don't even need side view mirrors 5. Allison 10 speed is learning and almost done with the hard shifts, but the power band is in it's sweet spot for every upshift. Extremely smooth and actually fast 6. Cab is more spacious and finally, rear HVAC vents are back 7. Tow mirrors are really big, harder to get used to, the power extend function is awesome 8. Satisfied!

They are cooled. They do have vents on the seat back, as well. I tried to explain that to them

It was the manager, they backed each other up, which is OK. My buddy has an 18, it blows much more and colder air. When I got home last night, I removed the rear seat cover to inspect the fans again. I took the foam inlet filter off and cleaned it thoroughly, it seemed to make a difference, this morning I got that "wet back" feeling, with the air being reasonably cool, just low flow. One mechanic did say that no matter how clean you keep your truck, the seat cushions still fill up with skin cells and micro debris, he recommended removing the seat covers and cleaning the cushions and covers to allow better flow. I think he may be onto something because they seem to push less air year after year. My '20 is on the line now, so my brother can deal with it, I just wanted it to be pristine when he gets it.

Update: The response I expected, like it's read from a script: "The seats are not cooled, only ventilated by cool cabin air. Try running the A/C on feet only and moving all obstructions from under and behind seat. The ventilation performance is based on the cabin air temperature and the cleanliness of the seat perforations". Well a couple of things to kill that theory: 1. This summer is on record for one of the coolest in Colorado history, and it's a garage queen, the interior never gets very hot. 2. I have tried the feet A/C vents and also took a dryer vent tube and piped one of the A/C vents right to the intake(s) on the seat. 3. Cleaned the seats again (they are immaculate any way) and then let A/C from the front vents blast them for about 5 minutes without me in them Result: as soon as your body temperature starts to warm the seats back up they blow warmer and warmer air to the point that it feels like a blow dryer. Before they quit blowing cold air, you could only stand them on high for about 5 minutes, it felt like your rear and back were wet. Disappointing!

My build sheet (20 2500 Duramax Denali Ultimate) lists PZ8 and PTT for the guidance and valve stems but no ZL6. If I remember correctly the only option I opted out of on my build was the ZL6 because I do not need the App, I only have a 5th wheel that I pull a handful of times per year. I did want the bed and guidance view along with the PTT. We tried and tried to figure out how to order the extra cameras, it looks as thought they are only available through GM accessories. The list above reflects that PZ8 can only be had with ZL6? Heck I don't know what I'm getting now.

Good point, maybe I will hit the local RV dealer and see if I can demo a 5th wheel-to-gooseneck adapter for one trip. All I would have to do it buy the ball, and return the adapter. It's worth a shot. I'm going to keep on Curt to see if they can nail down a date when available.

my '20 hit the line today, I emailed Curt as well, they are in the process of design. I asked if it would be available by Labor Day weekend and it was a maybe. I'm SOL, if not, I have camping reservations and will have a lonely 5ht wheel sitting in the driveway without a hitch to pull it with. I expect the truck here by 8/15, if I cannot get the hitch in time, it may sit on the back lot for 2 weeks.

OK, it's definitely worth a try. I just got off of the phone with the dealer and the service guy was actually pretty honest about it. He said they get about 20 appointments a week about seats and there is really nothing they can do. I know mine are not working because they actually seem hotter with the cooler on high. The good new is my '20 Duramax Denali Ultimate is being built, as we speak. My brother is buying this truck and I just wanted it to be in tip top shape when he does.

Thank you, I was able to pull the cover off far enough to see everything was intact, wires look good and all harness are plugged in. The semiconductor cooler does not seem to function at all anymore, but it was both seats all at once doesn’t make sense. Fuses are good. I am still wondering if the seat memory re flash had anything to do with it. I realized you have to be careful with the cushion and the elements. They are all attached to the cushion using spray adhesive tend to tear the foam rubber if you get too rough. Maybe it’s a trip to the dealer

Does the cooler route through the memory module? The reason I ask is I had it reflashed when my mirrors would not fold in? I’m sure if it is plugged in the firmware would still be intact. My blowers still work, there is only one fuse for each seat for heat and cool. The heat function still works so I figured no sense in wasting time looking at a good fuse. Maybe for sanity sake I will. From the post above it sounds as though I can remove the cover with ease to see if the cooler is functioning