Mine took dang near 1000 miles to move off of full. I have not used the DEF at truck stops yet, so I do not know about the nozzles.

 

I had a 2017 ford dually that traded of at 37000 miles for a def heater issue. Traded for 2021 ram dually five miles from dealership derate warning came on. Dealer said first def pump froze now saying just overfilled. In studying this found a you tube video. Motor city garage I believe that has a video with a pump removed and a simulated def tank.
Def is corrosive to metal, manufacturers are using sonar gauges to conquer this problem. When the tank is full will be def above the sonar and it will not start reading until it is exposed to air.
As far as ram goes dont know. Drove the ford home just with dealer plate

 

Have you figured out why it is stuck and how to fix it since your last post?

 

I have a new diesel also. I didn't have my DEF gauge move for a couple thousand miles. I pulled my trailer from FL to TX and back and I saw the DEF gauge drop. I am just hit 5K miles and my DEF Guage is about a 1/3 full. I hope this helps.

 

DEF tank i believe holds 8 gallons
8 gallons should go about 10,000 miles

when you have about 9,000 miles, you should get a warning
let it get too low & you will be walking to find some DEF

 

DEF gauge

I bought a Ram 3500 dually about a month ago. I have about 1400 miles on it and the DEF gauge has not moved off FULL. I was worried so I bought a gallon of DEF and put it in. I almost had the entire gallon in when the filler tube overflowed. I guess I still had plenty in the tank. I was just concerned after reading about the cutbacks if you run out.

 

I bought a Ram 3500 dually about a month ago. I have about 1400 miles on it and the DEF gauge has not moved off FULL. I was worried so I bought a gallon of DEF and put it in. I almost had the entire gallon in when the filler tube overflowed. I guess I still had plenty in the tank. I was just concerned after reading about the cutbacks if you run out.

I hope you washed off the overflow quite well, I hear its quite harmful to vehicle paint.

Also I have yet to find a truck stop with a filler- is it just like a gas(diesel) pump? If so, does it auto turn off when the DEF tank is full?

 

It hardly moves at time and then other times it goes quickly. I have not figured it out quite yet, but I'm sure you gauge is working fine.
I pull a trailer and when I do this the gauge hardly moves, this is because the engine is burning up the fuel better than when driving pulling nothing. That I figured out so far

 

DEF only enters the exhaust system
it does not enter the engine at all

http://www.youtube.com/watch?v=uQHvi2Lgnac

 

I had a problem with the DEF gauge showing dead empty when I overfilled the tank a bit using a DEF pump at a gas station (2018 Ram 2500). It also threw a check engine light but gave me no derate warning. After draining a gallon or so out, the gauge worked fine and the check engine light was able to be cleared. Before I did that, I stopped in at the dealer who told me I needed a new sensor and pump to the tune of > $2,000. I fixed it easily myself with the help from a Youtube video on how to drain the DEF tank and the price of some tubing and a primer bulb. Lesson learned and, needless to say, I won't be trusting that dealership with my business ever again.

 

I had a problem with the DEF gauge showing dead empty when I overfilled the tank a bit using a DEF pump at a gas station (2018 Ram 2500). It also threw a check engine light but gave me no derate warning. After draining a gallon or so out, the gauge worked fine and the check engine light was able to be cleared. Before I did that, I stopped in at the dealer who told me I needed a new sensor and pump to the tune of > $2,000. I fixed it easily myself with the help from a Youtube video on how to drain the DEF tank and the price of some tubing and a primer bulb. Lesson learned and, needless to say, I won't be trusting that dealership with my business ever again.

Nice video , thanks for the info . I am very hesitant to trust any ram dealer, lots of misinformed advisers or just plain Lies .

 

2018 RAM 3500 Cummins. My DEF gauge was stuck on half for 550 miles, so I put in a full jug (2.5ga) of DEF and the gauge shot up to 100%. I drove on another 300 miles and the gauge is still at 100%. No codes yet. Any ideas?

 

DEF does last a while. 2-3 tanks of fuel. Delete it all your truck will run better longer. Somehow mine now says full on the gage with nothing there. Must have a computer reprogram for that.