Hi, I have a 05 3500 5.9 that I like and plan to keep for a while yet.
The stock radio/ disc/ nav infinity radio is acting up…… would anyone know if there is a replacement from an aftermarket supplier that would fit without any modifications to the dash?
Nav and bluetooth would be a plus.

You should be able to find one on Ebay with no trouble. Most of the better brands have interchangeable harnesses that mate to the factory plug.

You can find stock replacements as well on the bay. Such good pricing I am seriously considering one for my 96 Suburban as they both are 1.5 DIN radios...

There are no longer any new 1.5 DIN aftermarket units.

There are new 1.5 din radios with out the nav. But you can buy a double din install kit with dash panel for less than $50. This complete set up looks pretty good.
http://www.ebay.com/itm/02-03-04-05-DODG...T-/271913847807

Thanks for the link, that has all the features I'm looking for.