International ProStar triangle is on and red light stop engine beeping but truck isok

The fuel gelled up?

 

Must be in Alaska. I don't think there is anywhere else that could have been cold enough.

The fact that you have that warning indicates that there really is something wrong, even if you don't think so.
Get it to a shop where they can check the codes.
If it is nothing, they can reset it.

Do it now before the engine de-rates, because you may be traveling at 5 MPH max.

 

Don't worry about anything suggesting the contrary, truck isok

 

If you're going to pick at someone's spelling you might want to proof read your own post for punctuation.

I'm going to make a guess that the "gelling" he's referring to is crystallized DEF clogging the injection valve. Whatever it is I'd be getting it back to a dealer asap.

 

The triangle means " look down here" at the digital display. At a minimum you need to do a parked regen. With the engine running push and hold the parked regen switch until the engine starts high revving. The regen can take as long as 45 minutes. Your gelled fuel caused a partial fuel burn which soot clogged your DPF.

If that doesn't work the DPF will have to be removed and baked to burn the soot out. Shop around and you should be able to find a better deal than $700.

Moose, it was 30* in Battle Mountain, NV last night and there was snow on the surrounding hills this morning.

Keith, the 2011 Prostar has the ISX 400 CUMMINS the last of the non DEF engines.

 

And you obviously didn't understand his sarcasm.