Fuel tank size

[Montanatom]

I have a 2008 Silverado 3500 DRW 8’ bed with the LLM engine.
The most fuel I have ever been able to put in is 21 gallons, and that is running till after the fuel warning goes off entirely. I have talked to several folks with the similar truck and they say that their fuel tank holds 34 gallons.
Has anybody had a similar issue, if so what’s the fix?

[Wing-in-it]

Your truck SHOULD have a 34 gallon tank......saying that, the 2008 model year is known for the “light” to come on prematurely. Best way to check is by checking for fuel mileage on paper to see if it is truly accurate.

Also I would check the option code sheet in your glove box to confirm it has the 34 gallon tank and NOT the 26 gallon one like my 2500 has.

[hornet28]

Long beds are 34 gal. I can't see po changing from 34 gal to 26 gal that the sb come with

[77cruiser]

Sensor in the tank could be bad. I've put 25 gal in my 26 gal. tank, yes i think I was cutting it close.

[77cruiser]

Here's a bit of reading for ya.
https://www.dieselplace.com/forum/63-gm-diesel-engines/140-duramax-third-generation-2006-2007-5-lbz-lly/720634-there-way-adjust-fuel-level-sensor.html


https://www.duramaxdiesels.com/forum/showthread.php?t=17791


https://www.google.com/search?client=firefox-b-1&q=duramax+fuel+gauge+fix&sa=X&ved=2ahUKEwjQ7sO5jsvfAhWMyoMKHWbeDlMQ1QIoAHoECAMQA Q&biw=1440&bih=739




https://www.google.com/search?client=firefox-b-1&q=duramax+fuel+gauge+incorrect&sa=X&ved=2ahUKEwjQ7sO5jsvfAhWMyoMKHWbeDlMQ1QIoAnoECAMQA w&biw=1440&bih=739