I've got a 2004 Ram 2500 Auto Trans. It is on the road/highway for 99+ % of my driving and I drive it about 5000 miles per year. I haven't had any kind of load on it or pulling for at least 2 years. Recently I was in one of those rare times out in the desert when I needed to use 4WD and for the first time ever I got an occasional high pitch squeak. I did not leave it in 4WD long enough to see if it went away if I drove it that way more than a few hundred yards, to warm up those parts involved that might not already be warmed up. Just for a test, I took it out today and tried it again, and again in a distance of maybe 1/4 mile it squeaked a few times. As I said it is a very high pitched squeak and didn't sound like anything in the differential, but just to be safe a checked the fluid in the differential and it appears to be as it should be. Any ideas what it might be? Should I be concerned? Should I take it out and drive it in 4WD for a longer distance and see if it goes away. Obviously I didn't already do that because I don't want to risk doing expensive damage.

Thanks for any help!!!

 

If it will do it at low speeds, have someone else drive, while you walk beside the truck, and see if you can hear where the noise is really coming from.