4wd not engaging
'99 3500 dually - 4wd worked fine this past summer when I had to go into low 4 to pull my boat out of the water. I haven't driven 1000 miles since then, and nothing else has changed, but when I went to engage the 4wd in the first snow of the year it stayed in 2 high when I moved the shifter to 4 high, and 4 low. The light never came on the dash either. There is no leaks on the drive, tranny hasn't complained. Any ideas?
Excuse my ignorance, I figured out how to search on this topic. It seems others have had issues like this and the point out the CAD is sticking. What am I looking for, and how do I tell if it's my issue? Is it an easy fix, or should I trust an expert? Thanks



