Ross McKenrick

I have a new 2021 Silverado (<5000mi) with a 3.0L Duramax diesel engine. I just completed a 4000 mile cross-country trip from Oregon to Massachusetts towing a 3600lb RV trailer and it quickly became apparent that I have a problem with the DEF system. When it is not towing, the truck is getting 25+ mpg, but I averaged approximately 10 mpg during this trip so I consumed about 400 gallons of diesel fuel. I am told that the DEF consumption should be in the range of 1-2% of the fuel consumption. Using this calculation, I should have consumed about 4-6 gallons of DEF. In actuality, I consumed 6 bottles (15 gallons) of DEF. I'm surprised that I didn't get better fuel and DEF consumption, but the most immediate problem is what appears to be faulty DEF sensors in the tank. Each time I filled the DEF tank, the DEF gauge would show full (8/8). After some number of miles (125?), the gauge would drop to 7/8, and then (after 250 miles) it would drop to empty. The info display would then flash "DEF Empty Refill Now" alternating with "500* mi Until 65 MPH Max Speed". *The 500 would count down until I stopped the truck and refilled the DEF -- which I would do within 5 miles. However, the DEF tank would overflow after pouring in about 2 gallons (from the 2.5 gallon bottle), spilling down the side of the truck, onto our shoes and leaving a puddle wherever we were. There may be a problem with our overall fuel and DEF consumption under tow--but I could live with that if the DEF sensors were working correctly and showed empty when the tank was actually empty and not 60% full. The truck is at the dealer now, but the dealer is having trouble pinpointing the problem. Is anyone else experiencing a similar problem with the DEF sensors / DEF gauge?

@DouglasHI have a new 2021 Silverado 1500 with a 3.0L Duramax. I just pulled my 4000lb teardrop RV trailer across the US and every 250 miles, the DEF gauge would drop from 7/8 full to empty and I would get the message "DEF tank is empty - refill now" alternating with "In 500 miles, your speed will be reduced". At this point, I would stop and refill the DEF tank, but it would only take 2 gallons--which is awkward since the bottles are 2.5 gallons and the only way to tell that the tank is full is when it overflows. The DEF tank sensors are not working correctly. I have taken it back to the dealer and they are struggling to find a solution.

I don't know about gear ratios or transmission cooling, but I want to share that I bought a Little Guy Max teardrop trailer with the following specs (dry weight 3010, tongue weight 310, GVWR 4000-4200): I then tried to pull it with a 2018 Toyota Highlander which has a rated towing capacity of 5000 lb. I tried pulling the trailer with it in Oregon, Nevada, Utah and Colorado. I was very unhappy with the reserve power--I was that guy driving at 60 mph going uphill with the four-way flashers on. Also, I was uncomfortable trying to pull the trailer through remote state parks -- up and down fairly steep unpaved roads to get to the nice camp sites. After about 2000 miles of towing, I had the car serviced and the front brakes were shot, the rear shocks were leaking, and the transmission (fluid) needed servicing. I traded the SUV in for a 2021 Silverado with a 3.0L Duramax diesel with a 10-speed transmission and the trailering package. Towing capacity of approx 9600. What a relief! Now I can accelerate going up hills if I want to and I can pull the trailer through pretty tough unpaved roads without worry. As a fairly new truck / trailer person, I recommend getting a truck with 2x the towing capacity of your trailer GVWR. Hth.

I think this is a software problem. I work for Microsoft and I just bought a new 2022 Chevy Silverado 1500 with a 3L diesel engine. We are on our initial cross-country trip towing a 4000 lb RV trailer. With 2500 miles on the speedometer, we have been through 5 2.5 gal bottles of DEF (in addition to what was in the truck when we pulled it off the lot). With a 5 gal DEF tank, I expected to be able to empty at least a 2.5 gal bottle of DEF into the tank when the tank was approaching empty. But no. Like the previous person, when the gauge says the DEF tank is empty, I am only able to add 2 gal of DEF before it overflows and makes a mess. I am completely confused by the message that says DEF empty and I have 500 miles before I am speed limited. I am convinced that the DEF tank is not empty, but I do have 500 mikes of range left. Yet I have to endure this dire message which takes over the dashboard screen for some 20 miles or so and then goes away. Meanwhile, the DEF level screen has only two readings, 7/8 full and empty. We need a software update. We need a better user experience so that we can live with this DEF system.