cNate

Traded my 2014 GMC Sierra SLT 1500 with 68k miles in for $30k. Sticker was $77k on my 2020 AT4 HD Duramax, paid $68,500 before tax, title, registration. That was last October. Sent from my iPhone using Tapatalk

My 2020 AT4 HD Duramax is a significant improvement over my 2014 1500 SLT. Agree with the HUD, 10 speed, and overall tech. For me, it’s towing. This thing was meant to tow and it does it beautifully. Bought the truck in October. Have put nearly 14k miles on it. Most of that towing our travel trailer all over the US throwing every environment at it. It’s exceeded expectations. Sent from my iPhone using Tapatalk

If you buy this adaptor and leave it in without a trailer, then you’ll get the mirror cameras to come on with the turn signal. Anyone sort out how to get all the other cameras to stay on beyond the 8 seconds? Would be useful for when the trick bed is loaded and going on down the road. Tow Ready 20142 7-Way Flat Pin to 7-Flat Plug to Plug Adapter, Regular Sent from my iPhone using Tapatalk

Anyone figured this mod out yet?? Sent from my iPhone using Tapatalk

So I’ve tracked about 1,600 miles since I topped off the DEF and did the module reprogram. Most of that was towing around California and out to Lake Havasu and back. Hit some grades and average slightly better on my MPG than my last hand calc on def (12 MPG versus my 11 MPG). Got 450 miles per gallon. Better than the 300-400 each time I hand calculated after 1k miles. The sensor also reads accurately all the time now. Will be i retesting to see if I can get close to the 1k per gal mark not towing. Been working remote due to covid and basically only leave if I have the travel trailer in tow these days. Sent from my iPhone using Tapatalk

You won’t be disappointed with the new truck and I’m sure you will really enjoy how much more capable your new truck is. Climbing and coming down steep grades is stress free now. I just completed a 5k mike round trip through rookies to Michigan and back. Truck handled everything I threw at it. Including going 75MPH legally in other states with no issue. 11k climb at 7% grade easy. High winds, heavy rain. No issue. Enjoy your new truck!!! Sent from my iPhone using Tapatalk

I just did the module reprogramming recall and topped off my DEF. I’m going to top it off after 1k miles and see what the mileage change is. Sent from my iPhone using Tapatalk

Done! Thanks! Sent from my iPhone using Tapatalk

Happy to hear you’re getting that kind of range not towing. I just did a 5k round trip towing and hand calculated each full up. Consistently saw between 300-400 per gallon depending on how fast and how much climbing. Sent from my iPhone using Tapatalk

Would be very happy to learn you’re getting 1k+ per gallon not towing!! Thanks! Sent from my iPhone using Tapatalk

Let us know how much you can get in there and if you’ve been towing. Dealership claimed upwards of 1k miles per gallon not towing. I’m surprised your dealership didn’t know about the service bulletin to reprogram the module. Could be because mine was manufactured last summer and purchased in October. Sent from my iPhone using Tapatalk

Just one trailer. I definitely didn’t have cell reception the whole time. But, when I’d check the data at the end of each day of hauling, the miles tied out in the app to the dash. Sent from my iPhone using Tapatalk

Doesn’t sound right. Have 12k miles on my truck. Probably 3/4 of that towing. Never experienced what you’re describing. Sent from my iPhone using Tapatalk

Just completed a 5k mike round trip towing. App, truck and sensors all worked fine. You may need to take the truck into the dealer. Something is off. Sent from my iPhone using Tapatalk

Likely your sensor is not working. I bet you could get 2-3 gallons in there if you fill it up. Sent from my iPhone using Tapatalk

Just brought the truck in for oil change, DEF top off, tire rotation, and replace the fuel filter (at 29% after 12k miles). Lots of towing so not getting anywhere near the 18-20k it’s expected to last. I asked them to check DEF system for recall or SERVICE BULLETIN and they found a software reprogram. They think it’ll help with the sensor reading the levels accurately now. I was having a problem where I fill up and it shows it was still half empty for a few hundred miles. My concern is more with the sensor because if the truck thinks it’s out of DEF and it’s not, then my speed will be limited. Sometimes it was showing full immediately. Software update likely won’t help with mileage. Techs thought 300-400 miles per gallon of DEF while towing was on par with what they’ve seen. Will report back after I put another 1k miles or so on the truck to let you know if it helps with sensor or burn rate. See bulletin number below. Sent from my iPhone using Tapatalk

Just brought the truck in for oil change, DEF top off, tire rotation, and replace the fuel filter (at 29% after 12k miles). Lots of towing so not getting anywhere near the 18-20k it’s expected to last. I asked them to check DEF system for recall or SERVICE BULLETIN and they found a software reprogram. They think it’ll help with the sensor reading the levels accurately now. I was having a problem where I fill up and it shows it was still half empty for a few hundred miles. Sometimes it was showing full immediately. Software update likely won’t help with mileage. Techs thought 300-400 miles per gallon of DEF while towing was on par with what they’ve seen. Will report back after I put another 1k miles or so on the truck to let you know if it helps with sensor or burn rate. See bulletin number below. Sent from my iPhone using Tapatalk

Appreciate all the great info on the thread. There’s another thread on this with a similar title and people are mentioning a DEF system recall, a program update and one person had to have their exhaust repaired which was causing over usage. Search DEF on 2020 forum for more info. Nate Sent from my iPhone using Tapatalk

Thank you. I was factoring each bar was a half gallon and added up all the bars. Appreciate you pointing it out in the manual. Sent from my iPhone using Tapatalk

I also have a 2020. Sent from my iPhone using Tapatalk

I posted a thread on this a few weeks back. I’m getting 300-400 per gallon towing 9k lbs trailer. My sensor misreads all the time. Just filled up and it shows half empty still. About 500 miles into a 2,500 mile trip over the next 5 days. Hoping I don’t end up in throttle mode limping down the highway because this sensor is off. Any way to reset the sensor? Sent from my iPhone using Tapatalk

Thanks for the reply, that kind of mileage is in-line with what I expected not towing. I have a 2020 with the L5P mated to the Allison 10 speed. I thought it was 7 gallons too but the manual says 5 gallons for my truck and when it’s down to one bar, I can only add back 4.5 gallons. Have you been able to put more than 5 in yours? Sent from my iPhone using Tapatalk

I know our tanks hold 5 gallons of DEF fluid. I seem to burn through a gallon about ever 300-400 miles when towing. Makes sense that it would burn faster while towing. Dealership said I should be getting closer to 1k miles per gallon on DEF. Even when I’m not towing, I’ve not seen anywhere near that number. Anyone else been tracking how many miles per gallon they burn? Towing/not towing? I don’t mind the cost of the DEF, just want to make sure I don’t get caught out in the dessert or mountains on crawl mode. I get pretty remote at times. I carry a couple boxes in the truck for long hauls. It’s also way cheaper if you fill up at truck stops versus buying Blue DEF online or at stores. Sent from my iPhone using Tapatalk

I did not have an issue the first 5k miles on the truck. The last 3k miles this has happened a handful of times. Those miles all came in the last few weeks on a long trip pulling my trailer. Sucked not having my Sirius XM, Spotify or WiFi periodically for the wife and kids. Especially, since I pay a lot extra per month for all that ******. I was wondering if it’s the satellite fin on the roof or if it’s software. To the person that took the fuse in and out, you’ve not had an issue since? How long has it been? Thanks, Nate Sent from my iPhone using Tapatalk

I want your garage! My 2020 AT4 HD doesn’t fit on the garage. My 35’ TT sits outside too. Would love to have indoor storage but here in So Cal that’s about $600 a month for the travel trailer. Sent from my iPhone using Tapatalk