I am getting a squeaking sound from the rear axle on my '01 2500 6sp, 2wd 3. 54g(105Kmi) from 0 to 15mph. Sounds like a mouse wheel that needs lube. Disconnected the U-joint from the yoke on the rearend thinking it might be the U-joint, it wasn't. Gear lube level also ok. No leaks. Squeak coming from where yoke inters the Dana 80 housing, sprayed some wd-40 on the seal just to see if it was internal (real expensive fix) or external (maybe not so expensive). The squeak stopped, but I know wd-40 isn't the solution.